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326 results on '"Ziurys, Lucy"'

53. Rotational Spectroscopy and Gas Phase Structures of Hydrogen Bonded Dimers, Organometallic Complexes and Other Molecules

Author

Lichtenberger, Dennis, Ziurys, Lucy, Huxter, Vanessa, Zhou, Zunwu, Lichtenberger, Dennis, Ziurys, Lucy, Huxter, Vanessa, and Zhou, Zunwu

Abstract

This dissertation focuses on the structural investigation of gas phase organometallic complexes, hydrogen-bonded dimers and other organic molecules through the use of pulsed-beam Fourier transform microwave spectroscopy technique and high-level computational methods. High-resolution microwave spectra and important structural parameters such as rotational constants and quadrupole coupling constants were measured and obtained for organometallic molecules ferrocenecarboxylic acid and methylmanganese pentacarbonyl, organic molecules 1-chloroborepin, phenylpropiolic acid and 2-aminopyridine, as well as hydrogen bonded dimer formamidinium formate. These studies have produced new important information for these molecules in regard to their gas phase structures, conformational behaviors, electronic charge distributions, chemical bonding and reactivity. Theoretical computations using Density Functional Theory (DFT) and ab initio methods were carried out to obtain optimized electronic structures of the molecules studied. The theoretical structures and parameters derived facilitated the scanning and assignment of rotational transitions. In addition, the comparisons between theoretically computed and experimentally determined structural parameters provide insights for structural determination of the molecules and other important molecular properties.

Published
2021

54. Fabrication of a Nb-based 180-degree IF hybrid for balanced SIS mixers

Author

Lysons, Christine M., Lichtenberger, Arthur W., Kerr, Anthony R., Lauria, Eugene F., and Ziurys, Lucy M.

Subjects
Integrated circuit fabrication -- Analysis, Microwave integrated circuits -- Design and construction, Mixers (Electronics) -- Design and construction, Integrated circuit fabrication, Business, Electronics, Electronics and electrical industries
Abstract

The fabrication of a compact Nb-based 180-degree hybrid for 4-12 GHz which could be applied for balanced superconductor-insulator-superconductor (SIS) mixers is discussed.

Published
2007

55. Event Horizon Telescope imaging of the archetypal blazar 3C 279 at an extreme 20 microarcsecond resolution

Author

Kim, Jae-Young, Krichbaum, Thomas P., Broderick, Avery E., Wielgus, Maciek, Blackburn, Lindy, Gomez, Jose L., Johnson, Michael D., Bouman, Katherine L., Chael, Andrew, Akiyama, Kazunori, Jorstad, Svetlana, Marscher, Alan P., Issaoun, Sara, Janssen, Michael, Chan, Chi-kwan, Savolainen, Tuomas, Pesce, Dominic W., Ozel, Feryal, Alberdi, Antxon, Alef, Walter, Asada, Keiichi, Azulay, Rebecca, Baczko, Anne-Kathrin, Ball, David, Balokovic, Mislav, Barrett, John, Bintley, Dan, Boland, Wilfred, Bower, Geoffrey C., Bremer, Michael, Brinkerink, Christiaan D., Brissenden, Roger, Britzen, Silke, Broguiere, Dominique, Bronzwaer, Thomas, Byun, Do-Young, Carlstrom, John E., Chatterjee, Shami, Chatterjee, Koushik, Chen, Ming-Tang, Chen, Yongjun, Cho, Ilje, Christian, Pierre, Conway, John E., Cordes, James M., Crew, Geoffrey B., Cui, Yuzhu, Davelaar, Jordy, De Laurentis, Mariafelicia, Deane, Roger, Dempsey, Jessica, Desvignes, Gregory, Dexter, Jason, Doeleman, Sheperd S., Eatough, Ralph P., Falcke, Heino, Fish, Vincent L., Fomalont, Ed, Fraga-Encinas, Raquel, Friberg, Per, Fromm, Christian M., Galison, Peter, Gammie, Charles F., Garcia, Roberto, Gentaz, Olivier, Georgiev, Boris, Goddi, Ciriaco, Gold, Roman, Gu, Minfeng, Gurwell, Mark, Hada, Kazuhiro, Hecht, Michael H., Hesper, Ronald, Ho, Luis C., Ho, Paul, Honma, Mareki, Huang, Chih-Wei L., Huang, Lei, Hughes, David H., Ikeda, Shiro, Inoue, Makoto, James, David J., Jannuzi, Buell T., Jeter, Britton, Jiang, Wu, Jimenez-Rosales, Alejandra, Jung, Taehyun, Karami, Mansour, Karuppusamy, Ramesh, Kawashima, Tomohisa, Keating, Garrett K., Kettenis, Mark, Kim, Junhan, Kim, Jongsoo, Kino, Motoki, Koay, Jun Yi, Koch, Patrick M., Koyama, Shoko, Kramer, Michael, Kramer, Carsten, Kuo, Cheng-Yu, Lauer, Tod R., Lee, Sang-Sung, Li, Yan-Rong, Li, Zhiyuan, Lindqvist, Michael, Lico, Rocco, Liu, Kuo, Liuzzo, Elisabetta, Lo, Wen-Ping, Lobanov, Andrei P., Loinard, Laurent, Lonsdale, Colin, Lu, Ru-Sen, MacDonald, Nicholas R., Mao, Jirong, Markoff, Sera, Marrone, Daniel P., Marti-Vidal, Ivan, Matsushita, Satoki, Matthews, Lynn D., Medeiros, Lia, Menten, Karl M., Mizuno, Yosuke, Mizuno, Izumi, Moran, James M., Moriyama, Kotaro, Moscibrodzka, Monika, Mueller, Cornelia, Nagai, Hiroshi, Nagar, Neil M., Nakamura, Masanori, Narayan, Ramesh, Narayanan, Gopal, Natarajan, Iniyan, Neri, Roberto, Ni, Chunchong, Noutsos, Aristeidis, Okino, Hiroki, Olivares, Hector, Ortiz-Leon, Gisela N., Oyama, Tomoaki, Palumbo, Daniel C. M., Park, Jongho, Patel, Nimesh, Pen, Ue-Li, Pietu, Vincent, Plambeck, Richard, PopStefanija, Aleksandar, Porth, Oliver, Prather, Ben, Preciado-Lopez, Jorge A., Psaltis, Dimitrios, Pu, Hung-Yi, Ramakrishnan, Venkatessh, Rao, Ramprasad, Rawlings, Mark G., Raymond, Alexander W., Rezzolla, Luciano, Ripperda, Bart, Roelofs, Freek, Rogers, Alan, Ros, Eduardo, Rose, Mel, Roshanineshat, Arash, Rottmann, Helge, Roy, Alan L., Ruszczyk, Chet, Ryan, Benjamin R., Rygl, Kazi L. J., Sanchez, Salvador, Sanchez-Arguelles, David, Sasada, Mahito, Schloerb, F. Peter, Schuster, Karl-Friedrich, Shao, Lijing, Shen, Zhiqiang, Small, Des, Sohn, Bong Won, SooHoo, Jason, Tazaki, Fumie, Tiede, Paul, Tilanus, Remo P. J., Titus, Michael, Toma, Kenji, Torne, Pablo, Trent, Tyler, Traianou, Efthalia, Trippe, Sascha, Tsuda, Shuichiro, van Bemmel, Ilse, van Langevelde, Huib Jan, van Rossum, Daniel R., Wagner, Jan, Wardle, John, Ward-Thompson, Derek, Weintroub, Jonathan, Wex, Norbert, Wharton, Robert, Wong, George N., Wu, Qingwen, Yoon, Doosoo, Young, Andre, Young, Ken, Younsi, Ziri, Yuan, Feng, Yuan, Ye-Fei, Zensus, J. Anton, Zhao, Guangyao, Zhao, Shan-Shan, Zhu, Ziyan, Algaba, Juan-Carlos, Allardi, Alexander, Amestica, Rodrigo, Anczarski, Jadyn, Bach, Uwe, Baganoff, Frederick K., Beaudoin, Christopher, Benson, Bradford A., Berthold, Ryan, Blanchard, Jay M., Blundell, Ray, Bustamente, Sandra, Cappallo, Roger, Castillo-Dominguez, Edgar, Chang, Chih-Cheng, Chang, Shu-Hao, Chang, Song-Chu, Chen, Chung-Chen, Chilson, Ryan, Chuter, Tim C., Rosado, Rodrigo Cordova, Coulson, Iain M., Crowley, Joseph, Derome, Mark, Dexter, Matthew, Dornbusch, Sven, Dudevoir, Kevin A., Dzib, Sergio A., Eckart, Andreas, Eckert, Chris, Erickson, Neal R., Everett, Wendeline B., Faber, Aaron, Farah, Joseph R., Fath, Vernon, Folkers, Thomas W., Forbes, David C., Freund, Robert, Gomez-Ruiz, Arturo, I, Gale, David M., Gao, Feng, Geertsema, Gertie, Graham, David A., Greer, Christopher H., Grosslein, Ronald, Gueth, Frederic, Haggard, Daryl, Halverson, Nils W., Han, Chih-Chiang, Han, Kuo-Chang, Hao, Jinchi, Hasegawa, Yutaka, Henning, Jason W., Hernandez-Gomez, Antonio, Herrero-Illana, Ruben, Heyminck, Stefan, Hirota, Akihiko, Hoge, James, Huang, Yau-De, Impellizzeri, C. M. Violette, Jiang, Homin, John, David, Kamble, Atish, Keisler, Ryan, Kimura, Kimihiro, Kono, Yusuke, Kubo, Derek, Kuroda, John, Lacasse, Richard, Laing, Robert A., Leitch, Erik M., Li, Chao-Te, Lin, Lupin C-C, Liu, Ching-Tang, Liu, Kuan-Yu, Lu, Li-Ming, Marson, Ralph G., Martin-Cocher, Pierre L., Massingill, Kyle D., Matulonis, Callie, McColl, Martin P., McWhirter, Stephen R., Messias, Hugo, Meyer-Zhao, Zheng, Michalik, Daniel, Montana, Alfredo, Montgomerie, William, Mora-Klein, Matias, Muders, Dirk, Nadolski, Andrew, Navarro, Santiago, Neilsen, Joseph, Nguyen, Chi H., Nishioka, Hiroaki, Norton, Timothy, Nowak, Michael A., Nystrom, George, Ogawa, Hideo, Oshiro, Peter, Parsons, Harriet, Penalver, Juan, Phillips, Neil M., Poirier, Michael, Pradel, Nicolas, Primiani, Rurik A., Raffin, Philippe A., Rahlin, Alexandra S., Reiland, George, Risacher, Christopher, Ruiz, Ignacio, Saez-Madain, Alejandro F., Sassella, Remi, Schellart, Pim, Shaw, Paul, Silva, Kevin M., Shiokawa, Hotaka, Smith, David R., Snow, William, Souccar, Kamal, Sousa, Don, Sridharan, T. K., Srinivasan, Ranjani, Stahm, William, Stark, Antony A., Story, Kyle, Timmer, Sjoerd T., Vertatschitsch, Laura, Walther, Craig, Wei, Ta-Shun, Whitehorn, Nathan, Whitney, Alan R., Woody, David P., Wouterloot, Jan G. A., Wright, Melvin, Yamaguchi, Paul, Yu, Chen-Yu, Zeballos, Milagros, Zhang, Shuo, Ziurys, Lucy, Kim, Jae-Young, Krichbaum, Thomas P., Broderick, Avery E., Wielgus, Maciek, Blackburn, Lindy, Gomez, Jose L., Johnson, Michael D., Bouman, Katherine L., Chael, Andrew, Akiyama, Kazunori, Jorstad, Svetlana, Marscher, Alan P., Issaoun, Sara, Janssen, Michael, Chan, Chi-kwan, Savolainen, Tuomas, Pesce, Dominic W., Ozel, Feryal, Alberdi, Antxon, Alef, Walter, Asada, Keiichi, Azulay, Rebecca, Baczko, Anne-Kathrin, Ball, David, Balokovic, Mislav, Barrett, John, Bintley, Dan, Boland, Wilfred, Bower, Geoffrey C., Bremer, Michael, Brinkerink, Christiaan D., Brissenden, Roger, Britzen, Silke, Broguiere, Dominique, Bronzwaer, Thomas, Byun, Do-Young, Carlstrom, John E., Chatterjee, Shami, Chatterjee, Koushik, Chen, Ming-Tang, Chen, Yongjun, Cho, Ilje, Christian, Pierre, Conway, John E., Cordes, James M., Crew, Geoffrey B., Cui, Yuzhu, Davelaar, Jordy, De Laurentis, Mariafelicia, Deane, Roger, Dempsey, Jessica, Desvignes, Gregory, Dexter, Jason, Doeleman, Sheperd S., Eatough, Ralph P., Falcke, Heino, Fish, Vincent L., Fomalont, Ed, Fraga-Encinas, Raquel, Friberg, Per, Fromm, Christian M., Galison, Peter, Gammie, Charles F., Garcia, Roberto, Gentaz, Olivier, Georgiev, Boris, Goddi, Ciriaco, Gold, Roman, Gu, Minfeng, Gurwell, Mark, Hada, Kazuhiro, Hecht, Michael H., Hesper, Ronald, Ho, Luis C., Ho, Paul, Honma, Mareki, Huang, Chih-Wei L., Huang, Lei, Hughes, David H., Ikeda, Shiro, Inoue, Makoto, James, David J., Jannuzi, Buell T., Jeter, Britton, Jiang, Wu, Jimenez-Rosales, Alejandra, Jung, Taehyun, Karami, Mansour, Karuppusamy, Ramesh, Kawashima, Tomohisa, Keating, Garrett K., Kettenis, Mark, Kim, Junhan, Kim, Jongsoo, Kino, Motoki, Koay, Jun Yi, Koch, Patrick M., Koyama, Shoko, Kramer, Michael, Kramer, Carsten, Kuo, Cheng-Yu, Lauer, Tod R., Lee, Sang-Sung, Li, Yan-Rong, Li, Zhiyuan, Lindqvist, Michael, Lico, Rocco, Liu, Kuo, Liuzzo, Elisabetta, Lo, Wen-Ping, Lobanov, Andrei P., Loinard, Laurent, Lonsdale, Colin, Lu, Ru-Sen, MacDonald, Nicholas R., Mao, Jirong, Markoff, Sera, Marrone, Daniel P., Marti-Vidal, Ivan, Matsushita, Satoki, Matthews, Lynn D., Medeiros, Lia, Menten, Karl M., Mizuno, Yosuke, Mizuno, Izumi, Moran, James M., Moriyama, Kotaro, Moscibrodzka, Monika, Mueller, Cornelia, Nagai, Hiroshi, Nagar, Neil M., Nakamura, Masanori, Narayan, Ramesh, Narayanan, Gopal, Natarajan, Iniyan, Neri, Roberto, Ni, Chunchong, Noutsos, Aristeidis, Okino, Hiroki, Olivares, Hector, Ortiz-Leon, Gisela N., Oyama, Tomoaki, Palumbo, Daniel C. M., Park, Jongho, Patel, Nimesh, Pen, Ue-Li, Pietu, Vincent, Plambeck, Richard, PopStefanija, Aleksandar, Porth, Oliver, Prather, Ben, Preciado-Lopez, Jorge A., Psaltis, Dimitrios, Pu, Hung-Yi, Ramakrishnan, Venkatessh, Rao, Ramprasad, Rawlings, Mark G., Raymond, Alexander W., Rezzolla, Luciano, Ripperda, Bart, Roelofs, Freek, Rogers, Alan, Ros, Eduardo, Rose, Mel, Roshanineshat, Arash, Rottmann, Helge, Roy, Alan L., Ruszczyk, Chet, Ryan, Benjamin R., Rygl, Kazi L. J., Sanchez, Salvador, Sanchez-Arguelles, David, Sasada, Mahito, Schloerb, F. Peter, Schuster, Karl-Friedrich, Shao, Lijing, Shen, Zhiqiang, Small, Des, Sohn, Bong Won, SooHoo, Jason, Tazaki, Fumie, Tiede, Paul, Tilanus, Remo P. J., Titus, Michael, Toma, Kenji, Torne, Pablo, Trent, Tyler, Traianou, Efthalia, Trippe, Sascha, Tsuda, Shuichiro, van Bemmel, Ilse, van Langevelde, Huib Jan, van Rossum, Daniel R., Wagner, Jan, Wardle, John, Ward-Thompson, Derek, Weintroub, Jonathan, Wex, Norbert, Wharton, Robert, Wong, George N., Wu, Qingwen, Yoon, Doosoo, Young, Andre, Young, Ken, Younsi, Ziri, Yuan, Feng, Yuan, Ye-Fei, Zensus, J. Anton, Zhao, Guangyao, Zhao, Shan-Shan, Zhu, Ziyan, Algaba, Juan-Carlos, Allardi, Alexander, Amestica, Rodrigo, Anczarski, Jadyn, Bach, Uwe, Baganoff, Frederick K., Beaudoin, Christopher, Benson, Bradford A., Berthold, Ryan, Blanchard, Jay M., Blundell, Ray, Bustamente, Sandra, Cappallo, Roger, Castillo-Dominguez, Edgar, Chang, Chih-Cheng, Chang, Shu-Hao, Chang, Song-Chu, Chen, Chung-Chen, Chilson, Ryan, Chuter, Tim C., Rosado, Rodrigo Cordova, Coulson, Iain M., Crowley, Joseph, Derome, Mark, Dexter, Matthew, Dornbusch, Sven, Dudevoir, Kevin A., Dzib, Sergio A., Eckart, Andreas, Eckert, Chris, Erickson, Neal R., Everett, Wendeline B., Faber, Aaron, Farah, Joseph R., Fath, Vernon, Folkers, Thomas W., Forbes, David C., Freund, Robert, Gomez-Ruiz, Arturo, I, Gale, David M., Gao, Feng, Geertsema, Gertie, Graham, David A., Greer, Christopher H., Grosslein, Ronald, Gueth, Frederic, Haggard, Daryl, Halverson, Nils W., Han, Chih-Chiang, Han, Kuo-Chang, Hao, Jinchi, Hasegawa, Yutaka, Henning, Jason W., Hernandez-Gomez, Antonio, Herrero-Illana, Ruben, Heyminck, Stefan, Hirota, Akihiko, Hoge, James, Huang, Yau-De, Impellizzeri, C. M. Violette, Jiang, Homin, John, David, Kamble, Atish, Keisler, Ryan, Kimura, Kimihiro, Kono, Yusuke, Kubo, Derek, Kuroda, John, Lacasse, Richard, Laing, Robert A., Leitch, Erik M., Li, Chao-Te, Lin, Lupin C-C, Liu, Ching-Tang, Liu, Kuan-Yu, Lu, Li-Ming, Marson, Ralph G., Martin-Cocher, Pierre L., Massingill, Kyle D., Matulonis, Callie, McColl, Martin P., McWhirter, Stephen R., Messias, Hugo, Meyer-Zhao, Zheng, Michalik, Daniel, Montana, Alfredo, Montgomerie, William, Mora-Klein, Matias, Muders, Dirk, Nadolski, Andrew, Navarro, Santiago, Neilsen, Joseph, Nguyen, Chi H., Nishioka, Hiroaki, Norton, Timothy, Nowak, Michael A., Nystrom, George, Ogawa, Hideo, Oshiro, Peter, Parsons, Harriet, Penalver, Juan, Phillips, Neil M., Poirier, Michael, Pradel, Nicolas, Primiani, Rurik A., Raffin, Philippe A., Rahlin, Alexandra S., Reiland, George, Risacher, Christopher, Ruiz, Ignacio, Saez-Madain, Alejandro F., Sassella, Remi, Schellart, Pim, Shaw, Paul, Silva, Kevin M., Shiokawa, Hotaka, Smith, David R., Snow, William, Souccar, Kamal, Sousa, Don, Sridharan, T. K., Srinivasan, Ranjani, Stahm, William, Stark, Antony A., Story, Kyle, Timmer, Sjoerd T., Vertatschitsch, Laura, Walther, Craig, Wei, Ta-Shun, Whitehorn, Nathan, Whitney, Alan R., Woody, David P., Wouterloot, Jan G. A., Wright, Melvin, Yamaguchi, Paul, Yu, Chen-Yu, Zeballos, Milagros, Zhang, Shuo, and Ziurys, Lucy

Abstract

3C 279 is an archetypal blazar with a prominent radio jet that show broadband flux density variability across the entire electromagnetic spectrum. We use an ultra-high angular resolution technique - global Very Long Baseline Interferometry (VLBI) at 1.3 mm (230 GHz) - to resolve the innermost jet of 3C 279 in order to study its fine-scale morphology close to the jet base where highly variable gamma -ray emission is thought to originate, according to various models. The source was observed during four days in April 2017 with the Event Horizon Telescope at 230 GHz, including the phased Atacama Large Millimeter/submillimeter Array (ALMA), at an angular resolution of similar to 20 mu as (at a redshift of z=0.536 this corresponds to similar to 0.13 pc similar to 1700 Schwarzschild radii with a black hole mass M-BH=8x10(8) M-circle dot). Imaging and model-fitting techniques were applied to the data to parameterize the fine-scale source structure and its variation. We find a multicomponent inner jet morphology with the northernmost component elongated perpendicular to the direction of the jet, as imaged at longer wavelengths. The elongated nuclear structure is consistent on all four observing days and across different imaging methods and model-fitting techniques, and therefore appears robust. Owing to its compactness and brightness, we associate the northern nuclear structure as the VLBI core. This morphology can be interpreted as either a broad resolved jet base or a spatially bent jet. We also find significant day-to-day variations in the closure phases, which appear most pronounced on the triangles with the longest baselines. Our analysis shows that this variation is related to a systematic change of the source structure. Two inner jet components move non-radially at apparent speeds of similar to 15 c and similar to 20 c (similar to 1.3 and similar to 1.7 mu as day(-1), respectively), which more strongly supports the scenario of traveling shocks or instabilities in a be

Published
2020

56. Gas-phase synthesis, submillimeter spectra, and precise structure of monomeric, solvent-free CuCH3

Author

Grotjahn, Douglas B., Halfen, DeWayne T., Ziurys, Lucy M., and Cooksy, Andrew L.

Subjects
Copper -- Chemical properties, Spectrum analysis -- Usage, Chemistry
Abstract

The synthesis of organocopper, methylcopper (CH3Cu) is detected using millimeter-wave rotational spectroscopy is presented. An obvious symmetric top pattern was observed, indicative of C (sub 3v) symmetry.

Published
2004

58. The first precise molecular structure of a monomeric transition metal cyanide, copper(I) cyanide

Author

Grotjahn, Douglas B., Brewster, M. A., and Ziurys, Lucy M.

Subjects
Cyanides -- Structure, Transition metal compounds -- Structure, Monomers -- Structure, Molecular structure -- Analysis, Chemistry
Abstract

The study reports the first preparation and precise structure of monomeric transition metal cyanide. Copper(I) cyanide is a very important reagent in organic, organometallic and supramolecular chemistry.

Published
2002

68. Event-horizon-scale structure in the supermassive black hole candidate at the Galactic Centre

Author

Doeleman, Sheperd S., Weintroub, Jonathan, Rogers, Alan E. E., Plambeck, Richard, Freund, Robert, Tilanus, Remo P. J., Friberg, Per, Ziurys, Lucy M., Moran, James M., Corey, Brian, Young, Ken H., Smythe, Daniel L., Titus, Michael, Marrone, Daniel P., Cappallo, Roger J., Bock, Douglas C.-J., Bower, Geoffrey C., Chamberlin, Richard, Davis, Gary R., Krichbaum, Thomas P., Lamb, James, Maness, Holly, Niell, Arthur E., Roy, Alan, Strittmatter, Peter, Werthimer, Daniel, Whitney, Alan R., and Woody, David

Published
2008
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69. A Multi-Wavelength Study of Parent Volatile Abundances in Comet C/2006 M4 (SWAN)

Author

DiSanti, Michael A, Villanueva, Geronimo L, Milam, Stefanie N, Zack, Lindsay N, Bonev, Boncho P, Mumma, Michael, Ziurys, Lucy M, and Anderson, William M

Subjects
Astronomy
Abstract

Volatile organic emissions were detected post-perihelion in the long period comet C/2006 M4 (SWAN) in October and November 2006. Our study combines target-of-opportunity, observations using the infrared Cryogenic Echelle Spectrometer (CSHELL) at the NASA-IRTF 3-m telescope, and millimeter wavelength observations using the Arizona Radio Observatory (ARO) 12-m telescope. Five parent volatiles were measured with CSHELL (H2O, CO, CH3OH, CH4, and C2H6), and two additional species (HCN and CS) were measured with the ARID 12-m. These revealed highly depleted CO and somewhat enriched CH3OH compared with abundances observed in the dominant group of long-period (Oort cloud) comets in our sample and similar to those observed recently in Comet 8P/Tuttle. This may indicate highly efficient H-atom addition to CO at very low temperature (approx.10-20 K) on the surfaces of interstellar (pre-cometary) grains. Comet C12006 M4 had nearly "normal" C2H6, and CH4, suggesting a processing history similar to that experienced by the dominant group. When compared with estimated water production at the time of the millimeter observations, HCN was slightly depleted compared with the normal abundance in comets based on 1R observations but was consistent with the majority of values from the millimeter. The ratio CS/HCN in C/2006 M4 was within the range measured in ten comets at millimeter wavelengths. The higher apparent H-atom conversion efficiency compared with most comets may indicate that the icy grains incorporated into C/2006 M4 were exposed to higher H-atom densities, or alternatively to similar densities but for a longer period of time.

Published
2009

71. First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole

Author

Akiyama, Kazunori, Alberdi, Antxon, Alef, Walter, Asada, Keiichi, Azulay, Rebecca, Baczko, Anne-Kathrin, Ball, David, Balokovic, Mislav, Barrett, John, Bintley, Dan, Blackburn, Lindy, Boland, Wilfred, Bouman, Katherine L., Bower, Geoffrey C., Bremer, Michael, Brinkerink, Christiaan D., Brissenden, Roger, Britzen, Silke, Broderick, Avery E., Broguiere, Dominique, Bronzwaer, Thomas, Byun, Do-Young, Carlstrom, John E., Chael, Andrew, Chan, Chi-kwan, Chatterjee, Shami, Chatterjee, Koushik, Chen, Ming-Tang, Chen, Yongjun, Cho, Ilje, Christian, Pierre, Conway, John E., Cordes, James M., Crew, Geoffrey B., Cui, Yuzhu, Davelaar, Jordy, De Laurentis, Mariafelicia, Deane, Roger, Dempsey, Jessica, Desvignes, Gregory, Dexter, Jason, Doeleman, Sheperd S., Eatough, Ralph P., Falcke, Heino, Fish, Vincent L., Fomalont, Ed, Fraga-Encinas, Raquel, Freeman, William T., Friberg, Per, Fromm, Christian M., Gomez, Jose L., Galison, Peter, Gammie, Charles F., Garcia, Roberto, Gentaz, Olivier, Georgiev, Boris, Goddi, Ciriaco, Gold, Roman, Gu, Minfeng, Gurwell, Mark, Hada, Kazuhiro, Hecht, Michael H., Hesper, Ronald, Ho, Luis C., Ho, Paul, Honma, Mareki, Huang, Chih-Wei L., Huang, Lei, Hughes, David H., Ikeda, Shiro, Inoue, Makoto, Issaoun, Sara, James, David J., Jannuzi, Buell T., Janssen, Michael, Jeter, Britton, Jiang, Wu, Johnson, Michael D., Jorstad, Svetlana, Jung, Taehyun, Karami, Mansour, Karuppusamy, Ramesh, Kawashima, Tomohisa, Keating, Garrett K., Kettenis, Mark, Kim, Jae-Young, Kim, Junhan, Kim, Jongsoo, Kino, Motoki, Koay, Jun Yi, Koch, Patrick M., Koyama, Shoko, Kramer, Michael, Kramer, Carsten, Krichbaum, Thomas P., Kuo, Cheng-Yu, Lauer, Tod R., Lee, Sang-Sung, Li, Yan-Rong, Li, Zhiyuan, Lindqvist, Michael, Liu, Kuo, Liuzzo, Elisabetta, Lo, Wen-Ping, Lobanov, Andrei P., Loinard, Laurent, Lonsdale, Colin, Lu, Ru-Sen, MacDonald, Nicholas R., Mao, Jirong, Markoff, Sera, Marrone, Daniel P., Marscher, Alan P., Marti-Vidal, Ivan, Matsushita, Satoki, Matthews, Lynn D., Medeiros, Lia, Menten, Karl M., Mizuno, Yosuke, Mizuno, Izumi, Moran, James M., Moriyama, Kotaro, Moscibrodzka, Monika, Mueller, Cornelia, Nagai, Hiroshi, Nagar, Neil M., Nakamura, Masanori, Narayan, Ramesh, Narayanan, Gopal, Natarajan, Iniyan, Neri, Roberto, Ni, Chunchong, Noutsos, Aristeidis, Okino, Hiroki, Olivares, Hector, Ortiz-Leon, Gisela N., Oyama, Tomoaki, Ozel, Feryal, Palumbo, Daniel C. M., Patel, Nimesh, Pen, Ue-Li, Pesce, Dominic W., Pietu, Vincent, Plambeck, Richard, PopStefanija, Aleksandar, Porth, Oliver, Prather, Ben, Preciado-Lopez, Jorge A., Psaltis, Dimitrios, Pu, Hung-Yi, Ramakrishnan, Venkatessh, Rao, Ramprasad, Rawlings, Mark G., Raymond, Alexander W., Rezzolla, Luciano, Ripperda, Bart, Roelofs, Freek, Rogers, Alan, Ros, Eduardo, Rose, Mel, Roshanineshat, Arash, Rottmann, Helge, Roy, Alan L., Ruszczyk, Chet, Ryan, Benjamin R., Rygl, Kazi L. J., Sanchez, Salvador, Sanchez-Arguelles, David, Sasada, Mahito, Savolainen, Tuomas, Schloerb, F. Peter, Schuster, Karl-Friedrich, Shao, Lijing, Shen, Zhiqiang, Small, Des, Sohn, Bong Won, SooHoo, Jason, Tazaki, Fumie, Tiede, Paul, Tilanus, Remo P. J., Titus, Michael, Toma, Kenji, Torne, Pablo, Trent, Tyler, Trippe, Sascha, Tsuda, Shuichiro, van Bemmel, Ilse, van Langevelde, Huib Jan, van Rossum, Daniel R., Wagner, Jan, Wardle, John, Weintroub, Jonathan, Wex, Norbert, Wharton, Robert, Wielgus, Maciek, Wong, George N., Wu, Qingwen, Young, Ken, Young, Andre, Younsi, Ziri, Yuan, Feng, Yuan, Ye-Fei, Zensus, J. Anton, Zhao, Guangyao, Zhao, Shan-Shan, Zhu, Ziyan, Algaba, Juan-Carlos, Allardi, Alexander, Amestica, Rodrigo, Anczarski, Jadyn, Bach, Uwe, Baganoff, Frederick K., Beaudoin, Christopher, Benson, Bradford A., Berthold, Ryan, Blanchard, Jay M., Blundell, Ray, Bustamente, Sandra, Cappallo, Roger, Castillo-Dominguez, Edgar, Chang, Chih-Cheng, Chang, Shu-Hao, Chang, Song-Chu, Chen, Chung-Chen, Chilson, Ryan, Chuter, Tim C., Rosado, Rodrigo Cordova, Coulson, Iain M., Crawford, Thomas M., Crowley, Joseph, David, John, Derome, Mark, Dexter, Matthew, Dornbusch, Sven, Dudevoir, Kevin A., Dzib, Sergio A., Eckart, Andreas, Eckert, Chris, Erickson, Neal R., Everett, Wendeline B., Faber, Aaron, Farah, Joseph R., Fath, Vernon, Folkers, Thomas W., Forbes, David C., Freund, Robert, Gomez-Ruiz, Arturo I., Gale, David M., Gao, Feng, Geertsema, Gertie, Graham, David A., Greer, Christopher H., Grosslein, Ronald, Gueth, Frederic, Haggard, Daryl, Halverson, Nils W., Han, Chih-Chiang, Han, Kuo-Chang, Hao, Jinchi, Hasegawa, Yutaka, Henning, Jason W., Hernandez-Gomez, Antonio, Herrero-Illana, Ruben, Heyminck, Stefan, Hirota, Akihiko, Hoge, James, Huang, Yau-De, Impellizzeri, C. M. Violette, Jiang, Homin, Kamble, Atish, Keisler, Ryan, Kimura, Kimihiro, Kono, Yusuke, Kubo, Derek, Kuroda, John, Lacasse, Richard, Laing, Robert A., Leitch, Erik M., Li, Chao-Te, Lin, Lupin C. -C., Liu, Ching-Tang, Liu, Kuan-Yu, Lu, Li-Ming, Marson, Ralph G., Martin-Cocher, Pierre L., Massingill, Kyle D., Matulonis, Callie, McColl, Martin P., McWhirter, Stephen R., Messias, Hugo, Meyer-Zhao, Zheng, Michalik, Daniel, Montana, Alfredo, Montgomerie, William, Mora-Klein, Matias, Muders, Dirk, Nadolski, Andrew, Navarro, Santiago, Neilsen, Joseph, Nguyen, Chi H., Nishioka, Hiroaki, Norton, Timothy, Nowak, Michael A., Nystrom, George, Ogawa, Hideo, Oshiro, Peter, Parsons, Harriet, Paine, Scott N., Penalver, Juan, Phillips, Neil M., Poirier, Michael, Pradel, Nicolas, Primiani, Rurik A., Raffin, Philippe A., Rahlin, Alexandra S., Reiland, George, Risacher, Christopher, Ruiz, Ignacio, Saez-Madain, Alejandro F., Sassella, Remi, Schellart, Pim, Shaw, Paul, Silva, Kevin M., Shiokawa, Hotaka, Smith, David R., Snow, William, Souccar, Kamal, Sousa, Don, Sridharan, T. K., Srinivasan, Ranjani, Stahm, William, Stark, Anthony A., Story, Kyle, Timmer, Sjoerd T., Vertatschitsch, Laura, Walther, Craig, Wei, Ta-Shun, Whitehorn, Nathan, Whitney, Alan R., Woody, David P., Wouterloot, Jan G. A., Wright, Melvin, Yamaguchi, Paul, Yu, Chen-Yu, Zeballos, Milagros, Zhang, Shuo, Ziurys, Lucy, Akiyama, Kazunori, Alberdi, Antxon, Alef, Walter, Asada, Keiichi, Azulay, Rebecca, Baczko, Anne-Kathrin, Ball, David, Balokovic, Mislav, Barrett, John, Bintley, Dan, Blackburn, Lindy, Boland, Wilfred, Bouman, Katherine L., Bower, Geoffrey C., Bremer, Michael, Brinkerink, Christiaan D., Brissenden, Roger, Britzen, Silke, Broderick, Avery E., Broguiere, Dominique, Bronzwaer, Thomas, Byun, Do-Young, Carlstrom, John E., Chael, Andrew, Chan, Chi-kwan, Chatterjee, Shami, Chatterjee, Koushik, Chen, Ming-Tang, Chen, Yongjun, Cho, Ilje, Christian, Pierre, Conway, John E., Cordes, James M., Crew, Geoffrey B., Cui, Yuzhu, Davelaar, Jordy, De Laurentis, Mariafelicia, Deane, Roger, Dempsey, Jessica, Desvignes, Gregory, Dexter, Jason, Doeleman, Sheperd S., Eatough, Ralph P., Falcke, Heino, Fish, Vincent L., Fomalont, Ed, Fraga-Encinas, Raquel, Freeman, William T., Friberg, Per, Fromm, Christian M., Gomez, Jose L., Galison, Peter, Gammie, Charles F., Garcia, Roberto, Gentaz, Olivier, Georgiev, Boris, Goddi, Ciriaco, Gold, Roman, Gu, Minfeng, Gurwell, Mark, Hada, Kazuhiro, Hecht, Michael H., Hesper, Ronald, Ho, Luis C., Ho, Paul, Honma, Mareki, Huang, Chih-Wei L., Huang, Lei, Hughes, David H., Ikeda, Shiro, Inoue, Makoto, Issaoun, Sara, James, David J., Jannuzi, Buell T., Janssen, Michael, Jeter, Britton, Jiang, Wu, Johnson, Michael D., Jorstad, Svetlana, Jung, Taehyun, Karami, Mansour, Karuppusamy, Ramesh, Kawashima, Tomohisa, Keating, Garrett K., Kettenis, Mark, Kim, Jae-Young, Kim, Junhan, Kim, Jongsoo, Kino, Motoki, Koay, Jun Yi, Koch, Patrick M., Koyama, Shoko, Kramer, Michael, Kramer, Carsten, Krichbaum, Thomas P., Kuo, Cheng-Yu, Lauer, Tod R., Lee, Sang-Sung, Li, Yan-Rong, Li, Zhiyuan, Lindqvist, Michael, Liu, Kuo, Liuzzo, Elisabetta, Lo, Wen-Ping, Lobanov, Andrei P., Loinard, Laurent, Lonsdale, Colin, Lu, Ru-Sen, MacDonald, Nicholas R., Mao, Jirong, Markoff, Sera, Marrone, Daniel P., Marscher, Alan P., Marti-Vidal, Ivan, Matsushita, Satoki, Matthews, Lynn D., Medeiros, Lia, Menten, Karl M., Mizuno, Yosuke, Mizuno, Izumi, Moran, James M., Moriyama, Kotaro, Moscibrodzka, Monika, Mueller, Cornelia, Nagai, Hiroshi, Nagar, Neil M., Nakamura, Masanori, Narayan, Ramesh, Narayanan, Gopal, Natarajan, Iniyan, Neri, Roberto, Ni, Chunchong, Noutsos, Aristeidis, Okino, Hiroki, Olivares, Hector, Ortiz-Leon, Gisela N., Oyama, Tomoaki, Ozel, Feryal, Palumbo, Daniel C. M., Patel, Nimesh, Pen, Ue-Li, Pesce, Dominic W., Pietu, Vincent, Plambeck, Richard, PopStefanija, Aleksandar, Porth, Oliver, Prather, Ben, Preciado-Lopez, Jorge A., Psaltis, Dimitrios, Pu, Hung-Yi, Ramakrishnan, Venkatessh, Rao, Ramprasad, Rawlings, Mark G., Raymond, Alexander W., Rezzolla, Luciano, Ripperda, Bart, Roelofs, Freek, Rogers, Alan, Ros, Eduardo, Rose, Mel, Roshanineshat, Arash, Rottmann, Helge, Roy, Alan L., Ruszczyk, Chet, Ryan, Benjamin R., Rygl, Kazi L. J., Sanchez, Salvador, Sanchez-Arguelles, David, Sasada, Mahito, Savolainen, Tuomas, Schloerb, F. Peter, Schuster, Karl-Friedrich, Shao, Lijing, Shen, Zhiqiang, Small, Des, Sohn, Bong Won, SooHoo, Jason, Tazaki, Fumie, Tiede, Paul, Tilanus, Remo P. J., Titus, Michael, Toma, Kenji, Torne, Pablo, Trent, Tyler, Trippe, Sascha, Tsuda, Shuichiro, van Bemmel, Ilse, van Langevelde, Huib Jan, van Rossum, Daniel R., Wagner, Jan, Wardle, John, Weintroub, Jonathan, Wex, Norbert, Wharton, Robert, Wielgus, Maciek, Wong, George N., Wu, Qingwen, Young, Ken, Young, Andre, Younsi, Ziri, Yuan, Feng, Yuan, Ye-Fei, Zensus, J. Anton, Zhao, Guangyao, Zhao, Shan-Shan, Zhu, Ziyan, Algaba, Juan-Carlos, Allardi, Alexander, Amestica, Rodrigo, Anczarski, Jadyn, Bach, Uwe, Baganoff, Frederick K., Beaudoin, Christopher, Benson, Bradford A., Berthold, Ryan, Blanchard, Jay M., Blundell, Ray, Bustamente, Sandra, Cappallo, Roger, Castillo-Dominguez, Edgar, Chang, Chih-Cheng, Chang, Shu-Hao, Chang, Song-Chu, Chen, Chung-Chen, Chilson, Ryan, Chuter, Tim C., Rosado, Rodrigo Cordova, Coulson, Iain M., Crawford, Thomas M., Crowley, Joseph, David, John, Derome, Mark, Dexter, Matthew, Dornbusch, Sven, Dudevoir, Kevin A., Dzib, Sergio A., Eckart, Andreas, Eckert, Chris, Erickson, Neal R., Everett, Wendeline B., Faber, Aaron, Farah, Joseph R., Fath, Vernon, Folkers, Thomas W., Forbes, David C., Freund, Robert, Gomez-Ruiz, Arturo I., Gale, David M., Gao, Feng, Geertsema, Gertie, Graham, David A., Greer, Christopher H., Grosslein, Ronald, Gueth, Frederic, Haggard, Daryl, Halverson, Nils W., Han, Chih-Chiang, Han, Kuo-Chang, Hao, Jinchi, Hasegawa, Yutaka, Henning, Jason W., Hernandez-Gomez, Antonio, Herrero-Illana, Ruben, Heyminck, Stefan, Hirota, Akihiko, Hoge, James, Huang, Yau-De, Impellizzeri, C. M. Violette, Jiang, Homin, Kamble, Atish, Keisler, Ryan, Kimura, Kimihiro, Kono, Yusuke, Kubo, Derek, Kuroda, John, Lacasse, Richard, Laing, Robert A., Leitch, Erik M., Li, Chao-Te, Lin, Lupin C. -C., Liu, Ching-Tang, Liu, Kuan-Yu, Lu, Li-Ming, Marson, Ralph G., Martin-Cocher, Pierre L., Massingill, Kyle D., Matulonis, Callie, McColl, Martin P., McWhirter, Stephen R., Messias, Hugo, Meyer-Zhao, Zheng, Michalik, Daniel, Montana, Alfredo, Montgomerie, William, Mora-Klein, Matias, Muders, Dirk, Nadolski, Andrew, Navarro, Santiago, Neilsen, Joseph, Nguyen, Chi H., Nishioka, Hiroaki, Norton, Timothy, Nowak, Michael A., Nystrom, George, Ogawa, Hideo, Oshiro, Peter, Parsons, Harriet, Paine, Scott N., Penalver, Juan, Phillips, Neil M., Poirier, Michael, Pradel, Nicolas, Primiani, Rurik A., Raffin, Philippe A., Rahlin, Alexandra S., Reiland, George, Risacher, Christopher, Ruiz, Ignacio, Saez-Madain, Alejandro F., Sassella, Remi, Schellart, Pim, Shaw, Paul, Silva, Kevin M., Shiokawa, Hotaka, Smith, David R., Snow, William, Souccar, Kamal, Sousa, Don, Sridharan, T. K., Srinivasan, Ranjani, Stahm, William, Stark, Anthony A., Story, Kyle, Timmer, Sjoerd T., Vertatschitsch, Laura, Walther, Craig, Wei, Ta-Shun, Whitehorn, Nathan, Whitney, Alan R., Woody, David P., Wouterloot, Jan G. A., Wright, Melvin, Yamaguchi, Paul, Yu, Chen-Yu, Zeballos, Milagros, Zhang, Shuo, and Ziurys, Lucy

Abstract

When surrounded by a transparent emission region, black holes are expected to reveal a dark shadow caused by gravitational light bending and photon capture at the event horizon. To image and study this phenomenon, we have assembled the Event Horizon Telescope, a global very long baseline interferometry array observing at a wavelength of 1.3 mm. This allows us to reconstruct event-horizon-scale images of the supermassive black hole candidate in the center of the giant elliptical galaxy M87. We have resolved the central compact radio source as an asymmetric bright emission ring with a diameter of 42 +/- 3 mu as, which is circular and encompasses a central depression in brightness with a flux ratio greater than or similar to 10: 1. The emission ring is recovered using different calibration and imaging schemes, with its diameter and width remaining stable over four different observations carried out in different days. Overall, the observed image is consistent with expectations for the shadow of a Kerr black hole as predicted by general relativity. The asymmetry in brightness in the ring can be explained in terms of relativistic beaming of the emission from a plasma rotating close to the speed of light around a black hole. We compare our images to an extensive library of ray-traced general-relativistic magnetohydrodynamic simulations of black holes and derive a central mass of M = (6.5 +/- 0.7) x 10(9) M-circle dot. Our radio-wave observations thus provide powerful evidence for the presence of supermassive black holes in centers of galaxies and as the central engines of active galactic nuclei. They also present a new tool to explore gravity in its most extreme limit and on a mass scale that was so far not accessible.

Published
2019

72. Laboratory Astrophysics White Paper

Author

Brickhouse, Nancy, Federman, Steve, Kwong, Victor, Salama, Farid, Savin, Daniel, Stancil, Phillip, Weingartner, Joe, and Ziurys, Lucy

Subjects
Astrophysics
Abstract

Laboratory astrophysics and complementary theoretical calculations are the foundations of astronomical and planetary research and will remain so for many generations to come. From the level of scientific conception to that of the scientific return, it is our understanding of the underlying processes that allows us to address fundamental questions regarding the origins and evolution of galaxies, stars, planetary systems, and life in the cosmos. In this regard, laboratory astrophysics is much like detector and instrument development at NASA and NSF; these efforts are necessary for the astronomical research being funded by the agencies. The NASA Laboratory Astrophysics Workshop met at the University of Nevada, Las Vegas (UNLV) from 14-16 February, 2006 to identify the current laboratory data needed to support existing and future NASA missions and programs in the Astrophysics Division of the Science Mission Directorate (SMD). Here we refer to both laboratory and theoretical work as laboratory astrophysics unless a distinction is necessary. The format for the Workshop involved invited talks by users of laboratory data, shorter contributed talks and poster presentations by both users and providers that highlighted exciting developments in laboratory astrophysics, and breakout sessions where users and providers discussed each others' needs and limitations. We also note that the members of the Scientific Organizing Committee are users as well as providers of laboratory data. As in previous workshops, the focus was on atomic, molecular, and solid state physics.

Published
2006

78. The electronic structure of vanadium monochloride cation (VCl+): Tackling the complexities of transition metal species.

Author

DeYonker, Nathan J., Halfen, DeWayne T., Allen, Wesley D., and Ziurys, Lucy M.

Subjects
VANADIUM compounds, ELECTRONIC structure, CATIONS, TRANSITION metal complexes, CHEMICAL species, VALENCE (Chemistry)
Abstract

Six electronic states (X 4∑-, A 4∏, B 4∆, ²Φ, ²∆, ²∑+) of the vanadium monochloride cation (VCl+) are described using large basis set coupled cluster theory. For the two lowest quartet states (X 4∑- and A 4∏), a focal point analysis (FPA) approach was used that conjoined a correlation-consistent family of basis sets up to aug-cc-pwCV5Z-DK with high-order coupled cluster theory through pentuple (CCSDTQP) excitations. FPA adiabatic excitation energies (T0) and spectroscopic constants (re, r0, Be, B0, De, He, ωe, v0, αe, ωe xe) were extrapolated to the valence complete basis set Douglas-Kroll (DK) aug-cc-pV∞Z-DK CCSDT level of theory, and additional treatments accounted for higher-order valence electron correlation, core correlation, and spin-orbit coupling. Due to the delicate interplay between dynamical and static electronic correlation, single reference coupled cluster theory is able to provide the correct ground electronic state (X 4∑-), while multireference configuration interaction theory cannot. Perturbations from the first- and second-order spin orbit coupling of low-lying states with quartet spin multiplicity reveal an immensely complex rotational spectrum relative to the isovalent species VO, VS, and TiCl. Computational data on the doublet manifold suggest that the lowest-lying doublet state (²Γ) has a Te of ~11200 cm-1. Overall, this study shows that laboratory and theoretical rotational spectroscopists must work more closely in tandem to better understand the bonding and structure of molecules containing transition metals. [ABSTRACT FROM AUTHOR]

Published
2014
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79. Microwave Spectra and Molecular Structures of Organic Molecules and Hydrogen Bonded Dimers

Author

Brown, Michael F., Lichtenberger, Dennis L., Ziurys, Lucy M., Pejlovas, Aaron Matthew, Brown, Michael F., Lichtenberger, Dennis L., Ziurys, Lucy M., and Pejlovas, Aaron Matthew

Abstract

The microwave spectra were measured in the 4-15 GHz regime for cyclopropanecarboxylic acid, 1,2-cyclohexanedione, maleimide, phthalimide, and 4a,8a-azaboranaphthalene. Doubly hydrogen bonded dimers formed with formic acid were also measured with the molecules cyclopropanecarboxylic acid, 1,2-cyclohexanedione, maleimide, and tropolone. Measurements were made using a pulsed beam Fourier transform microwave spectrometer. Rotational and centrifugal distortion constants were determined from the microwave spectra. In the case of the systems that exhibit electric quadrupole coupling interactions, the electric quadrupole coupling strengths were also determined from the analysis of the hyperfine structure in the spectra, yielding additional electronic structure information for the molecules studied. The spectra were also measured for a number of unique, singly substituted isotopologues under natural abundance concentrations. This isotopologue data is crucial in order to obtain key gas phase molecular structure parameters of the molecules and complexes studied. Many theoretical computations, using ab initio and DFT methods, were also performed to obtain optimized electronic structures of the systems studied. These computations aid in the search and assignments of the rotational transitions measured. Comparisons between the theory and the experimental results are described in greater detail in the respective chapters for those systems. The experimental results for the organic systems studied agreed well (within a few percent) with the gas phase optimization computations performed.

Published
2018

86. Detection of Intrinsic Source Structure at ∼3 Schwarzschild Radii with Millimeter-VLBI Observations of SAGITTARIUS A*

Author

Lu, Ru-Sen, primary, Krichbaum, Thomas P., additional, Roy, Alan L., additional, Fish, Vincent L., additional, Doeleman, Sheperd S., additional, Johnson, Michael D., additional, Akiyama, Kazunori, additional, Psaltis, Dimitrios, additional, Alef, Walter, additional, Asada, Keiichi, additional, Beaudoin, Christopher, additional, Bertarini, Alessandra, additional, Blackburn, Lindy, additional, Blundell, Ray, additional, Bower, Geoffrey C., additional, Brinkerink, Christiaan, additional, Broderick, Avery E., additional, Cappallo, Roger, additional, Crew, Geoffrey B., additional, Dexter, Jason, additional, Dexter, Matt, additional, Falcke, Heino, additional, Freund, Robert, additional, Friberg, Per, additional, Greer, Christopher H., additional, Gurwell, Mark A., additional, Ho, Paul T. P., additional, Honma, Mareki, additional, Inoue, Makoto, additional, Kim, Junhan, additional, Lamb, James, additional, Lindqvist, Michael, additional, Macmahon, David, additional, Marrone, Daniel P., additional, Martí-Vidal, Ivan, additional, Menten, Karl M., additional, Moran, James M., additional, Nagar, Neil M., additional, Plambeck, Richard L., additional, Primiani, Rurik A., additional, Rogers, Alan E. E., additional, Ros, Eduardo, additional, Rottmann, Helge, additional, SooHoo, Jason, additional, Spilker, Justin, additional, Stone, Jordan, additional, Strittmatter, Peter, additional, Tilanus, Remo P. J., additional, Titus, Michael, additional, Vertatschitsch, Laura, additional, Wagner, Jan, additional, Weintroub, Jonathan, additional, Wright, Melvyn, additional, Young, Ken H., additional, Zensus, J. Anton, additional, and Ziurys, Lucy M., additional

Published
2018
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87. The rotational spectrum and dynamical structure of LiOH and LiOD: A combined laboratory and ab initio study.

Author

Higgins, Kelly J., Freund, Samuel M., Klemperer, William, Apponi, Aldo J., and Ziurys, Lucy M.

Subjects
SPECTRUM analysis, POTENTIAL energy surfaces, DIPOLE moments, ISOTOPES, MOLECULAR shapes, PHYSICS
Abstract

Millimeter wave rotational spectroscopy and ab initio calculations are used to explore the potential energy surface of LiOH and LiOD with particular emphasis on the bending states and bending potential. New measurements extend the observed rotational lines to J=7←6 for LiOH and J=8←7 for LiOD for all bending vibrational states up to (0330). Rotation-vibration energy levels, geometric expectation values, and dipole moments are calculated using extensive high-level ab initio three-dimensional potential energy and dipole moment surfaces. Agreement between calculation and experiment is superb, with predicted Bv values typically within 0.3%, D values within 0.2%, ql values within 0.7%, and dipole moments within 0.9% of experiment. Shifts in Bv values with vibration and isotopic substitution are also well predicted. A combined theoretical and experimental structural analysis establishes the linear equilibrium structure with re(Li–O)=1.5776(4) Å and re(O–H)=0.949(2) Å. Predicted fundamental vibrational frequencies are v1=923.2, v2=318.3, and v3=3829.8 cm-1 for LiOH and v1=912.9, v2=245.8, and v3=2824.2 cm-1 for LiOD. The molecule is extremely nonrigid with respect to angular deformation; the calculated deviation from linearity for the vibrationally averaged structure is 19.0° in the (000) state and 41.9° in the (0330) state. The calculation not only predicts, in agreement with previous work [P. R. Bunker, P. Jensen, A. Karpfen, and H. Lischka, J. Mol. Spectrosc. 135, 89 (1989)], a change from a linear to a bent minimum energy configuration at elongated Li–O distances, but also a similar change from linear to bent at elongated O–H distances. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Published
2004
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88. Laboratory Studies of Methane and Its Relationship to Prebiotic Chemistry

Author

Kobayashi, Kensei, Geppert, Wolf D., Carrasco, Nathalie, Holm, Nils G., Mousis, Olivier, Palumbo, Maria Elisabetta, Waite, J. Hunter, Watanabe, Naoki, Ziurys, Lucy M., Kobayashi, Kensei, Geppert, Wolf D., Carrasco, Nathalie, Holm, Nils G., Mousis, Olivier, Palumbo, Maria Elisabetta, Waite, J. Hunter, Watanabe, Naoki, and Ziurys, Lucy M.

Abstract

To examine how prebiotic chemical evolution took place on Earth prior to the emergence of life, laboratory experiments have been conducted since the 1950s. Methane has been one of the key molecules in these investigations. In earlier studies, strongly reducing gas mixtures containing methane and ammonia were used to simulate possible reactions in the primitive atmosphere of Earth, producing amino acids and other organic compounds. Since Earth's early atmosphere is now considered to be less reducing, the contribution of extraterrestrial organics to chemical evolution has taken on an important role. Such organic molecules may have come from molecular clouds and regions of star formation that created protoplanetary disks, planets, asteroids, and comets. The interstellar origin of organics has been examined both experimentally and theoretically, including laboratory investigations that simulate interstellar molecular reactions. Endogenous and exogenous organics could also have been supplied to the primitive ocean, making submarine hydrothermal systems plausible sites of the generation of life. Experiments that simulate such hydrothermal systems where methane played an important role have consequently been conducted. Processes that occur in other Solar System bodies offer clues to the prebiotic chemistry of Earth. Titan and other icy bodies, where methane plays significant roles, are especially good targets. In the case of Titan, methane is both in the atmosphere and in liquidospheres that are composed of methane and other hydrocarbons, and these have been studied in simulation experiments. Here, we review the wide range of experimental work in which these various terrestrial and extraterrestrial environments have been modeled, and we examine the possible role of methane in chemical evolution.

Published
2017
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90. Activation of methane by zinc: gas-phase synthesis, structure, and bonding of HZnC[H.sub.3]

Author

Flory, Michael A., Apponi, Aldo J., Zack, Lindsay N., and Ziurys, Lucy M.

Subjects
Zinc compounds -- Chemical properties, Methane -- Chemical properties, Chemical reactions -- Analysis, Hydrogen -- Chemical properties, Chemistry
Abstract

The methylzinc hydride molecule (HZnC[H.sub.3]) is observed in the gas phase in the monomeric form, where the molecule is prepared by the reaction of dimethylzinc with hydrogen gas and methane in an AC discharge and the reaction of zinc vapor produced in a Broida-type oven with methane in a DC discharge. The studies have shown that HZnC[H.sub.3] is formed through the oxidative addition of zinc to methane in the gas phase and HZnC[H.sub.3] is the first metal-methane insertion complex is structurally characterized.

Published
2010

91. Competition between metal-amido and metal imido chemistries in the alkaline earth series: An experimental and theoretical study of BaNH

Author

Janczyk, Alexandra, Lichtenberger, Dennis L., and Ziurys, Lucy M.

Subjects
Barium compounds -- Structure, Barium compounds -- Electric properties, Barium compounds -- Chemical properties, Density functionals -- Analysis, Oxidation-reduction reaction -- Analysis, Chemistry
Abstract

The pure rotational spectrum of BaNH in its X(super 1)SIGMA(super +) ground electronic state is recorded using millimeters/submillimeter direct absorption methods. It is noted that the reaction of the Ba atom with amidogen continues on to the imidogen continues on to the amido species, due to the greater ease of oxidation of the Ba atom, and the greater strength of the Ba-NH pi bonds.

Published
2006

97. 230 GHz VLBI observations of M87: event-horizon-scale structure at the enhanced very-high-energy $\rm ��$-ray state in 2012

Author

Akiyama, Kazunori, Lu, Ru-Sen, Fish, Vincent L., Doeleman, Sheperd S., Broderick, Avery E., Dexter, Jason, Hada, Kazuhiro, Kino, Motoki, Nagai, Hiroshi, Honma, Mareki, Johnson, Michael D., Algaba, Juan C., Asada, Keiichi, Brinkerink, Christiaan, Blundell, Ray, Bower, Geoffrey C., Cappallo, Roger, Crew, Geoffrey B., Dexter, Matt, Dzib, Sergio A., Freund, Robert, Friberg, Per, Gurwell, Mark, Ho, Paul T. P., Inoue, Makoto, Krichbaum, Thomas P., Loinard, Laurent, MacMahon, David, Marrone, Daniel P., Moran, James M., Nakamura, Masanori, Nagar, Neil M., Ortiz-Leon, Gisela, Plambeck, Richard, Pradel, Nicolas, Primiani, Rurik A., Rogers, Alan E. E., Roy, Alan L., SooHoo, Jason, Tavares, Jonathan-Le��n, Tilanus, Remo P. J., Titus, Michael, Wagner, Jan, Weintroub, Jonathan, Yamaguchi, Paul, Young, Ken H., Zensus, Anton, and Ziurys, Lucy M.

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Astrophysics::High Energy Astrophysical Phenomena, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

We report on 230 GHz (1.3 mm) VLBI observations of M87 with the Event Horizon Telescope using antennas on Mauna Kea in Hawaii, Mt. Graham in Arizona and Cedar Flat in California. For the first time, we have acquired 230 GHz VLBI interferometric phase information on M87 through measurement of closure phase on the triangle of long baselines. Most of the measured closure phases are consistent with 0$^{\circ}$ as expected by physically-motivated models for 230 GHz structure such as jet models and accretion disk models. The brightness temperature of the event-horizon-scale structure is $\sim 1 \times 10^{10}$ K derived from the compact flux density of $\sim 1$ Jy and the angular size of $\sim 40 $ $\rm ��$as $\sim$ 5.5 $R_{\rm s}$, which is broadly consistent with the peak brightness of the radio cores at 1-86 GHz located within $\sim 10^2$ $R_{\rm s}$. Our observations occurred in the middle of an enhancement in very-high-energy (VHE) $\rm ��$-ray flux, presumably originating in the vicinity of the central black hole. Our measurements, combined with results of multi-wavelength observations, favor a scenario in which the VHE region has an extended size of $\sim$20-60 $R_{\rm s}$., 11 pages, 4 figures, accepted to ApJ

Published
2015
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98. Terahertz Spectroscopy of 25MgH (X2Σ+) and 67ZnH (X2Σ+): Bonding in Simple Metal Hydrides

Author

Bucchino, Matthew P. and Ziurys, Lucy Marie

Abstract

Pure rotational spectra of 25MgH (X2Σ+) and 67ZnH (X2Σ+) were recorded using direct absorption techniques. These free radicals were synthesized by the reaction of metal vapor, generated in a Broida-type oven, with H2in a dc discharge. The N = 0 → 1 and N = 1 → 2 transitions were recorded for both species in the frequency range of 342 – 789 GHz. Spin-rotation and metal and proton hyperfine interactions were resolved in the spectra. From these data, rotational, fine structure, and hyperfine constants were determined, including the Fermi contact, dipolar, and electric quadrupole parameters of the 25Mg and 67Zn nuclei. Comparison of the metal and proton hyperfine terms suggests that the unpaired electron resides in a σ molecular orbital that has significant s contributions from both the metal and the hydrogen atoms. The dipolar terms for both metals are relatively large, in contrast to those of the proton, and indicate spσ and possibly sdσ (zinc only) orbital hybridization. The quadrupole constants arise principally from the p/d orbital character of the unpaired electron, although there is a non-negligible polarization contribution. These results suggest significant covalent character in both MgH and ZnH, in contrast to their fluoride analogs.

Published
2024
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99. Rotational Spectroscopy of Simple Metal Carbon Clusters: Resolving the Beauty of Fine and Hyperfine Interactions in Metal Monoacetylides and Metal Carbides

Author

Ziurys, Lucy M., Brown, Michael, Miranda, Katrina, Sanov, Andrei, Randtke, Jie Min, Ziurys, Lucy M., Brown, Michael, Miranda, Katrina, Sanov, Andrei, and Randtke, Jie Min

Abstract

Pure rotational spectra of simple metal carbon clusters that relevant to transition metal synthesis and catalysis have been obtained using Fourier transform microwave (FTMW) techniques combined with millimeter-wave direct-absorption methods. Rotational spectra of metal acetylides (CuCCH, ZnCCH, Li/Na/KCCH, MgCCH, AlCCH, CrCCH), diatomic metal monocarbide (CrC) and T-shape metal dicarbides (YC₂ and ScC₂) were recorded in the 4–650 GHz frequency regime. Measurements of weaker isotoplogues including ⁶⁶ZnCCH, ⁶⁸ZnCCH, Zn¹³C¹³CH, ZnCCD, Li/Na/KCCD, CrCCD, Y¹³C¹²C, Y¹³C¹³C, Sc¹³C¹³C, were also studied to aid in structural determinations. This work is the first study of ZnCCH and ScC₂ by any type of spectroscopic technique. Hyperfine splittings in MgCCH and Li/Na/KCCH have also been resolved and the weak isotoplogues of YC₂ have been measured for the first time. Potential interstellar molecules ScO and FeCN were studied using the FTMW techniques in the 4–62 GHz frequency regime. Spectra of the zinc insertion product ClZnCH₃ were additionally recorded in the 10–30 GHz (FTMW) and 260–296 GHz (direct absorption) frequency ranges, along with weaker isotopologues Cl⁶⁶ZnCH₃ and Cl⁶⁸ZnCH₃. This works is the first measurement of zinc insertion products using the FTMW-DALAS techniques. The data were analyzed implementing an effective Hamiltonian, allowing for accurate spectroscopic parameters to be established. From rotational constants, the molecular geometries were accurately determined. Electronic properties were also assessed, including the degree of covalent vs ionic character in a chemical bond, and the molecular orbital composition. The fundamental physical and chemical properties of these benchmark species were obtained in order to gain insight into their role in larger molecular systems, test theoretical calculations, and, in certain cases, provide accurate rest frequencies for astronomical searches.

Published
2016

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