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16 results on '"Schoenlein, R. W."'

1. Evidence for a structurally-driven insulator-to-metal transition in VO2: A view from the ultrafast timescale

Author

Cavalleri, A., Dekorsy, T., Chon, H. H. W., Kiefer, J. C., Schoenlein, R. W., Cavalleri, A., Dekorsy, T., Chon, H. H. W., Kiefer, J. C., and Schoenlein, R. W.

Abstract

We apply ultrafast spectroscopy to establish a time-domain hierarchy between structural and electronic effects in a strongly correlated electron system. We discuss the case of the model system VO2, a prototypical nonmagnetic compound that exhibits cell doubling, charge localization, and a metal-insulator transition below 340 K. We initiate the formation of the metallic phase by prompt hole photo-doping into the valence band of the low-T insulator. The insulator-to-metal transition is, however, delayed with respect to hole injection, exhibiting a bottleneck time scale, associated with the phonon connecting the two crystallographic phases. This structural bottleneck is observed despite faster depletion of the d bands and is indicative of important bandlike character for this controversial insulator.

Published
2004

5. Femtosecond X-ray Spectroscopy Directly Quantifies Transient Excited-State Mixed Valency

Author

Liekhus-Schmaltz, Chelsea, Fox, Zachary W., Andersen, Amity, Kjaer, Kasper S., Alonso-Mori, Roberto, Biasin, Elisa, Carlstad, Julia, Chollet, Matthieu, Gaynor, James D., Glownia, James M., Hong, Kiryong, Kroll, Thomas, Lee, Jae Hyuk, Poulter, Benjamin, Reinhard, Marco, Sokaras, Dimosthenis, Zhang, Yu, Doumy, Gilles, March, Anne Marie, Southworth, Stephen H., Mukamel, Shaul, Cordones, Amy A., Schoenlein, Robert W., Govind, Niranjan, Khalil, Munira, Liekhus-Schmaltz, Chelsea, Fox, Zachary W., Andersen, Amity, Kjaer, Kasper S., Alonso-Mori, Roberto, Biasin, Elisa, Carlstad, Julia, Chollet, Matthieu, Gaynor, James D., Glownia, James M., Hong, Kiryong, Kroll, Thomas, Lee, Jae Hyuk, Poulter, Benjamin, Reinhard, Marco, Sokaras, Dimosthenis, Zhang, Yu, Doumy, Gilles, March, Anne Marie, Southworth, Stephen H., Mukamel, Shaul, Cordones, Amy A., Schoenlein, Robert W., Govind, Niranjan, and Khalil, Munira

Abstract

Quantifying charge delocalization associated with short-lived photoexcited states of molecular complexes in solution remains experimentally challenging, requiring local element specific femtosecond experimental probes of time-evolving electron transfer. In this study, we quantify the evolving valence hole charge distribution in the photoexcited charge transfer state of a prototypical mixed valence bimetallic iron-ruthenium complex, [(CN)5(FeIICNRuIII)(NH3)5]-, in water by combining femtosecond X-ray spectroscopy measurements with time-dependent density functional theory calculations of the excited-state dynamics. We estimate the valence hole charge that accumulated at the Fe atom to be 0.6 ± 0.2, resulting from excited-state metal-to-metal charge transfer, on an ∼60 fs time scale. Our combined experimental and computational approach provides a spectroscopic ruler for quantifying excited-state valency in solvated complexes.

Published
2022

6. Direct observation of coherent femtosecond solvent reorganization coupled to intramolecular electron transfer

Author

Biasin, Elisa, Fox, Zachary W., Andersen, Amity, Ledbetter, Kathryn, Kjær, Kasper S., Alonso-Mori, Roberto, Carlstad, Julia M., Chollet, Matthieu, Gaynor, James D., Glownia, James M., Hong, Kiryong, Kroll, Thomas, Lee, Jae Hyuk, Liekhus-Schmaltz, Chelsea, Reinhard, Marco, Sokaras, Dimosthenis, Zhang, Yu, Doumy, Gilles, March, Anne Marie, Southworth, Stephen H., Mukamel, Shaul, Gaffney, Kelly J., Schoenlein, Robert W., Govind, Niranjan, Cordones, Amy A., Khalil, Munira, Biasin, Elisa, Fox, Zachary W., Andersen, Amity, Ledbetter, Kathryn, Kjær, Kasper S., Alonso-Mori, Roberto, Carlstad, Julia M., Chollet, Matthieu, Gaynor, James D., Glownia, James M., Hong, Kiryong, Kroll, Thomas, Lee, Jae Hyuk, Liekhus-Schmaltz, Chelsea, Reinhard, Marco, Sokaras, Dimosthenis, Zhang, Yu, Doumy, Gilles, March, Anne Marie, Southworth, Stephen H., Mukamel, Shaul, Gaffney, Kelly J., Schoenlein, Robert W., Govind, Niranjan, Cordones, Amy A., and Khalil, Munira

Abstract

It is well known that the solvent plays a critical role in ultrafast electron-transfer reactions. However, solvent reorganization occurs on multiple length scales, and selectively measuring short-range solute–solvent interactions at the atomic level with femtosecond time resolution remains a challenge. Here we report femtosecond X-ray scattering and emission measurements following photoinduced charge-transfer excitation in a mixed-valence bimetallic (FeiiRuiii) complex in water, and their interpretation using non-equilibrium molecular dynamics simulations. Combined experimental and computational analysis reveals that the charge-transfer excited state has a lifetime of 62 fs and that coherent translational motions of the first solvation shell are coupled to the back electron transfer. Our molecular dynamics simulations identify that the observed coherent translational motions arise from hydrogen bonding changes between the solute and nearby water molecules upon photoexcitation, and have an amplitude of tenths of ångströms, 120–200 cm−1 frequency and ~100 fs relaxation time. This study provides an atomistic view of coherent solvent reorganization mediating ultrafast intramolecular electron transfer. [Figure not available: see fulltext.]

Published
2021

7. Using Ultrafast X-ray Spectroscopy To Address Questions in Ligand-Field Theory: The Excited State Spin and Structure of [Fe(dcpp)2]2

Author

Britz, Alexander, Gawelda, Wojciech, Assefa, Tadesse A., Jamula, Lindsey L., Yarranton, Jonathan T., Galler, Andreas, Khakhulin, Dmitry, Diez, Michael, Harder, Manuel, Doumy, Gilles, March, Anne Marie, Bajnóczi, Éva, Németh, Zoltán, Pápai, Mátyás Imre, Rozsályi, Emese, Sárosiné Szemes, Dorottya, Cho, Hana, Mukherjee, Sriparna, Liu, Chang, Kim, Tae Kyu, Schoenlein, Robert W., Southworth, Stephen H., Young, Linda, Jakubikova, Elena, Huse, Nils, Vankó, György, Bressler, Christian, McCusker, James K., Britz, Alexander, Gawelda, Wojciech, Assefa, Tadesse A., Jamula, Lindsey L., Yarranton, Jonathan T., Galler, Andreas, Khakhulin, Dmitry, Diez, Michael, Harder, Manuel, Doumy, Gilles, March, Anne Marie, Bajnóczi, Éva, Németh, Zoltán, Pápai, Mátyás Imre, Rozsályi, Emese, Sárosiné Szemes, Dorottya, Cho, Hana, Mukherjee, Sriparna, Liu, Chang, Kim, Tae Kyu, Schoenlein, Robert W., Southworth, Stephen H., Young, Linda, Jakubikova, Elena, Huse, Nils, Vankó, György, Bressler, Christian, and McCusker, James K.

Abstract

We have employed a range of ultrafast X-ray spectroscopies in an effort to characterize the lowest energy excited state of [Fe(dcpp)2]2+ (where dcpp is 2,6-(dicarboxypyridyl)pyridine). This compound exhibits an unusually short excited-state lifetime for a low-spin Fe(II) polypyridyl complex of 270 ps in a room-temperature fluid solution, raising questions as to whether the ligand-field strength of dcpp had pushed this system beyond the 5T2/3T1 crossing point and stabilizing the latter as the lowest energy excited state. Kα and Kβ X-ray emission spectroscopies have been used to unambiguously determine the quintet spin multiplicity of the long-lived excited state, thereby establishing the 5T2 state as the lowest energy excited state of this compound. Geometric changes associated with the photoinduced ligand-field state conversion have also been monitored with extended X-ray absorption fine structure. The data show the typical average Fe-ligand bond length elongation of ∼0.18 Å for a 5T2 state and suggest a high anisotropy of the primary coordination sphere around the metal center in the excited 5T2 state, in stark contrast to the nearly perfect octahedral symmetry that characterizes the low-spin 1A1 ground state structure. This study illustrates how the application of time-resolved X-ray techniques can provide insights into the electronic structures of molecules-in particular, transition metal complexes-that are difficult if not impossible to obtain by other means.

Published
2019

8. Ligand-field symmetry effects in Fe(II) polypyridyl compounds probed by transient X-ray absorption spectroscopy

Author

Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Cho, Hana, Strader, Matthew L., Hong, Kiryong, Jamula, Lindsey, Gullikson, Eric M., Kim, Tae Kyu, de Groot, Frank M. F., McCusker, James K., Schoenlein, Robert W., Huse, Nils, Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Cho, Hana, Strader, Matthew L., Hong, Kiryong, Jamula, Lindsey, Gullikson, Eric M., Kim, Tae Kyu, de Groot, Frank M. F., McCusker, James K., Schoenlein, Robert W., and Huse, Nils

Published
2012

9. Ligand-field symmetry effects in Fe(II) polypyridyl compounds probed by transient X-ray absorption spectroscopy

Author

Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Cho, Hana, Strader, Matthew L., Hong, Kiryong, Jamula, Lindsey, Gullikson, Eric M., Kim, Tae Kyu, de Groot, Frank M. F., McCusker, James K., Schoenlein, Robert W., Huse, Nils, Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Cho, Hana, Strader, Matthew L., Hong, Kiryong, Jamula, Lindsey, Gullikson, Eric M., Kim, Tae Kyu, de Groot, Frank M. F., McCusker, James K., Schoenlein, Robert W., and Huse, Nils

Published
2012

10. Ligand-field symmetry effects in Fe(II) polypyridyl compounds probed by transient X-ray absorption spectroscopy

Author

Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Cho, Hana, Strader, Matthew L., Hong, Kiryong, Jamula, Lindsey, Gullikson, Eric M., Kim, Tae Kyu, de Groot, Frank M. F., McCusker, James K., Schoenlein, Robert W., Huse, Nils, Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Cho, Hana, Strader, Matthew L., Hong, Kiryong, Jamula, Lindsey, Gullikson, Eric M., Kim, Tae Kyu, de Groot, Frank M. F., McCusker, James K., Schoenlein, Robert W., and Huse, Nils

Published
2012

11. Femtosecond Soft X-ray Spectroscopy of Solvated Transition-Metal Complexes: Deciphering the Interplay of Electronic and Structural Dynamics

Author

Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Huse, Nils, Cho, Hana, Hong, Kiryong, Jamula, Lindsey, de Groot, Frank M. F., Kim, Tae Kyu, McCusker, James K., Schoenlein, Robert W., Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Huse, Nils, Cho, Hana, Hong, Kiryong, Jamula, Lindsey, de Groot, Frank M. F., Kim, Tae Kyu, McCusker, James K., and Schoenlein, Robert W.

Published
2011

12. Femtosecond Soft X-ray Spectroscopy of Solvated Transition-Metal Complexes: Deciphering the Interplay of Electronic and Structural Dynamics

Author

Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Huse, Nils, Cho, Hana, Hong, Kiryong, Jamula, Lindsey, de Groot, Frank M. F., Kim, Tae Kyu, McCusker, James K., Schoenlein, Robert W., Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Huse, Nils, Cho, Hana, Hong, Kiryong, Jamula, Lindsey, de Groot, Frank M. F., Kim, Tae Kyu, McCusker, James K., and Schoenlein, Robert W.

Published
2011

13. Femtosecond Soft X-ray Spectroscopy of Solvated Transition-Metal Complexes: Deciphering the Interplay of Electronic and Structural Dynamics

Author

Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Huse, Nils, Cho, Hana, Hong, Kiryong, Jamula, Lindsey, de Groot, Frank M. F., Kim, Tae Kyu, McCusker, James K., Schoenlein, Robert W., Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Huse, Nils, Cho, Hana, Hong, Kiryong, Jamula, Lindsey, de Groot, Frank M. F., Kim, Tae Kyu, McCusker, James K., and Schoenlein, Robert W.

Published
2011

14. Photo-Induced Spin-State Conversion in Solvated Transition Metal Complexes Probed via Time-Resolved Soft X-ray Spectroscopy

Author

Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Huse, Nils, Kim, Tae Kyu, Jamula, Lindsey, McCusker, James K., de Groot, Frank M. F., Schoenlein, Robert W., Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Huse, Nils, Kim, Tae Kyu, Jamula, Lindsey, McCusker, James K., de Groot, Frank M. F., and Schoenlein, Robert W.

Published
2010

15. Photo-Induced Spin-State Conversion in Solvated Transition Metal Complexes Probed via Time-Resolved Soft X-ray Spectroscopy

Author

Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Huse, Nils, Kim, Tae Kyu, Jamula, Lindsey, McCusker, James K., de Groot, Frank M. F., Schoenlein, Robert W., Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Huse, Nils, Kim, Tae Kyu, Jamula, Lindsey, McCusker, James K., de Groot, Frank M. F., and Schoenlein, Robert W.

Published
2010

16. Photo-Induced Spin-State Conversion in Solvated Transition Metal Complexes Probed via Time-Resolved Soft X-ray Spectroscopy

Author

Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Huse, Nils, Kim, Tae Kyu, Jamula, Lindsey, McCusker, James K., de Groot, Frank M. F., Schoenlein, Robert W., Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis, Huse, Nils, Kim, Tae Kyu, Jamula, Lindsey, McCusker, James K., de Groot, Frank M. F., and Schoenlein, Robert W.

Published
2010

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