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556 results on '"Buma, W.J."'

3. A visible-light-driven molecular motor based on barbituric acid

Author

Kuntze, K., Pooler, D.R.S., Di Donato, M., Hilbers, M.F., van der Meulen, P., Buma, W.J., Priimagi, A., Feringa, B.L., Crespi, S., Kuntze, K., Pooler, D.R.S., Di Donato, M., Hilbers, M.F., van der Meulen, P., Buma, W.J., Priimagi, A., Feringa, B.L., and Crespi, S.

Abstract

Contains fulltext : 295506.pdf (Publisher’s version ) (Open Access)

Published
2023

4. Mechanistic Basis for Red Light Switching of Azonium Ions

Author

Medved’, M., Di Donato, M., Buma, W.J., Laurent, A.D., Lameijer, L., Hrivnák, T., Romanov, I., Tran, S., Feringa, B.L., Szymanski, W., Woolley, G.A., Medved’, M., Di Donato, M., Buma, W.J., Laurent, A.D., Lameijer, L., Hrivnák, T., Romanov, I., Tran, S., Feringa, B.L., Szymanski, W., and Woolley, G.A.

Abstract

Contains fulltext : 296755.pdf (Publisher’s version ) (Closed access)

Published
2023

7. Activating a light-driven molecular motor by metal complexation

Author

Stindt, C.N., Crespi, S., Toyoda, R., Hilbers, M.F., Kemmink, J., Meulen, P. van der, Buma, W.J., Feringa, B.L., Stindt, C.N., Crespi, S., Toyoda, R., Hilbers, M.F., Kemmink, J., Meulen, P. van der, Buma, W.J., and Feringa, B.L.

Abstract

Item does not contain fulltext

Published
2023

9. Anharmonicity and deuteration in the IR absorption and emission spectrum of phenylacetylene

Author

Esposito, V., Ferrari, Piero, Buma, W.J., Boersma, Christiaan, Mackie, C.J., Candian, Alessandra, Fortenberry, Ryan C., Tielens, Alexander G.G.M., Esposito, V., Ferrari, Piero, Buma, W.J., Boersma, Christiaan, Mackie, C.J., Candian, Alessandra, Fortenberry, Ryan C., and Tielens, Alexander G.G.M.

Abstract

Item does not contain fulltext

Published
2023

12. Controlling forward and backward rotary molecular motion on demand

Author

Pfeifer, Lukas, Crespi, Stefano, Meulen, P. van der, Kemmink, J., Scheek, R.M., Hilbers, Michiel F., Buma, W.J., Feringa, B.L., Pfeifer, Lukas, Crespi, Stefano, Meulen, P. van der, Kemmink, J., Scheek, R.M., Hilbers, Michiel F., Buma, W.J., and Feringa, B.L.

Abstract

Contains fulltext : 250167.pdf (Publisher’s version ) (Open Access)

Published
2022

13. Towards developing novel and sustainable molecular light-to-heat converters

Author

Abiola, Temitope T., Rioux, Benjamin, Toldo, Josene M., Alarcan, Jimmy, Woolley, Jack M., Turner, M.A., Buma, W.J., Stavros, Vasilios G., Allais, Florent, Abiola, Temitope T., Rioux, Benjamin, Toldo, Josene M., Alarcan, Jimmy, Woolley, Jack M., Turner, M.A., Buma, W.J., Stavros, Vasilios G., and Allais, Florent

Abstract

Contains fulltext : 240860.pdf (Publisher’s version ) (Open Access)

Published
2021

14. Phenylimino Indolinone: A Green-Light-Responsive T-Type Photoswitch Exhibiting Negative Photochromism

Author

Crespi, Stefano, Simeth, Nadja A., Donato, M., Doria, Sandra, Stindt, Charlotte N., Hilbers, Michiel F., Buma, W.J., Feringa, Ben L., Szymanski, W., Crespi, Stefano, Simeth, Nadja A., Donato, M., Doria, Sandra, Stindt, Charlotte N., Hilbers, Michiel F., Buma, W.J., Feringa, Ben L., and Szymanski, W.

Abstract

Contains fulltext : 240091.pdf (Publisher’s version ) (Open Access)

Published
2021

17. Allosteric Guest Binding in Chiral Zirconium(IV) Double Decker Porphyrin Cages

Author

Bruekers, J.P.J., Hellinghuizen, M.A., Vanthuyne, N., Tinnemans, P., Gilissen, P.J., Buma, W.J., Elemans, Johannes A.A.W., Nolte, R.J.M., Bruekers, J.P.J., Hellinghuizen, M.A., Vanthuyne, N., Tinnemans, P., Gilissen, P.J., Buma, W.J., Elemans, Johannes A.A.W., and Nolte, R.J.M.

Abstract

Contains fulltext : 229006.pdf (publisher's version ) (Open Access)

Published
2021

19. Temperature-dependent modulation by biaryl-based monomers of the chain length and morphology of biphenyl-based supramolecular polymers

Author

Iseki, Tomokazu, Mabesoone, M.F.J., Koenis, Mark A.J., Lamers, Brigitte A.G., Weyandt, Elisabeth, Windt, Lafayette N.J. de, Buma, W.J., Palmans, Anja R.A., Meijer, E.W., Iseki, Tomokazu, Mabesoone, M.F.J., Koenis, Mark A.J., Lamers, Brigitte A.G., Weyandt, Elisabeth, Windt, Lafayette N.J. de, Buma, W.J., Palmans, Anja R.A., and Meijer, E.W.

Abstract

Contains fulltext : 238830.pdf (Publisher’s version ) (Open Access)

Published
2021

25. Far-IR Absorption of Neutral Polycyclic Aromatic Hydrocarbons (PAHs): Light on the Mechanism of IR–UV Ion Dip Spectroscopy

Author

Lemmens, A.K., Rap, D.B., Thunnissen, J.M.M., Gruet, S., Steber, A.L., Panchagnula, S., Tielens, A.G.G.M., Schnell, M., Buma, W.J., Rijs, A.M., Lemmens, A.K., Rap, D.B., Thunnissen, J.M.M., Gruet, S., Steber, A.L., Panchagnula, S., Tielens, A.G.G.M., Schnell, M., Buma, W.J., and Rijs, A.M.

Abstract

Contains fulltext : 227107.pdf (publisher's version ) (Open Access)

Published
2020

31. Using density functional based tight binding methods in vibrational circular dichroism

Author

Teodoro, T., Koenis, M., Galembeck, S., Nicu, P., Buma, W.J., Visscher, L., and Molecular Spectroscopy (HIMS, FNWI)

Abstract

Theoretical calculations of vibrational properties are widely used to explain and predict experimental spectra. An example is the interpretation of vibrational circular dichroism (VCD) spectra, for which the absolute configuration of chiral systems can determined by comparing measured and calculated spectra. For large organic molecules that have many assessible conformations, the computational cost of density functional theory (DFT) calculations is considerable and often a limiting factor for practical applications. We have investigated alternatives in which density functional based tight binding (DFTB) is used in parts or all stages of the calculation. DFTB is shown to perform reasonably well at the first stage, yielding frequencies and normal modes in line with DFT data. With standard parametrizations dipole gradients needed in the second stage are, however, poorly reproduced, and improvement using information obtained by DFT calculation is necessary. As typically only a specific spectral region is of experimental interest, we have thereby developed an efficient method to calculate only a specific part of the spectrum. After the computationally very cheap DFTB estimate of the molecular motions, the computational time is proportional to the number of normal modes needed to describe this frequency range. Results for a medium-sized molecule show a reduction in computational time of up to one order of magnitude with negligible loss in accuracy. We also show that still larger computational savings are possible by using an additional intensity-selection procedure.

Published
2019

32. Two ground state conformers of the proton sponge 1,8-bis(dimetyhlamino)naphthalene revealed by fluorescence spectroscopy and ab initio calculations

Author

Szemik-Hojniak, A., Zwier, J.M., Buma, W.J., Bursi, R., and Waals, J.H., van der

Subjects
Acid-base chemistry -- Research, Naphthalene -- Research, Aromatic compounds -- Research, Nitrogen compounds -- Research, Proteins -- Conformation, Chemistry
Abstract

Photophysical properties of 1,8-bis(dimethylamino)naphthalene (DMAN) were analyzed using fluorescence excitation spectroscopy on supersonic beam expansions. Vibronic intensities in the excitation spectrum and the temperature dependence of this spectrum indicate that DMAN assumes at least two conformations in its electronic ground state. The most stable conformation produces spectra similar to those of substituted naphthalene derivatives. Ab initio calculations validate the existence of two stable minima on the potential energy surface of the electronic ground state.

Published
1998

34. Analytical chemistry on many-center chiral compounds based on vibrational circular dichroism: Absolute configuration assignments and determination of contaminant levels

Author

Koenis, Mark A.J., Tiekink, Eveline H., Raamsdonk, Davita M.E. van, Joosten, Nadav U., Gooijer, Susanne A., Nicu, Valentin P., Visscher, L., Buma, W.J., Koenis, Mark A.J., Tiekink, Eveline H., Raamsdonk, Davita M.E. van, Joosten, Nadav U., Gooijer, Susanne A., Nicu, Valentin P., Visscher, L., and Buma, W.J.

Abstract

Item does not contain fulltext

Published
2019

36. Ab-initio calculations on vibronic coupling in the lower triplet states of pyrimidine

Author

Buma, W.J., Donckers, M.C.J.M., and Groenen, E.J.J.

Subjects
Pyrimidines -- Research, Chemical bonds -- Research, Chemistry
Abstract

Studies on pyrimidine with optimized geometry at unrestricted Hartree-Fock and complete active space self-consistent field reveal that both the states are affected by strong vibronic coupling. The pyrimidine in the lowest triplet state possesses a dynamic out-of-plane distortion. The predicted in-plane geometry changes are in agreement with results obtained from optically detected electron nuclear double resonance experiments.

Published
1992

37. Enantiospecific Brook Rearrangement of Tertiary Benzylic α-Hydroxysilanes

Author

Collados, J.F., Ortiz, P., Pérez, J.M., Xia, Y., Koenis, M.A.J., Buma, W.J., Nicu, V.P., Harutyunyan, S.R., and Molecular Spectroscopy (HIMS, FNWI)

Abstract

The Brook rearrangement of simple, chiral tertiary benzylic -hydroxysilanes is presented. The rearrangement followed by proton trapping is enantiospecific and proceeds with inversion of the configuration at the carbon center. Importantly, the [1,2]-Brook rearrangement can be followed by trapping of methyl or allyl electrophiles even in the protic environment, although with minimal retention of chirality.

Published
2018

39. The anharmonic quartic force field infrared spectra of hydrogenated and methylated PAHs

Author

Mackie, C.J., Candian, A., Huang, X., Maltseva, E., Petrignani, A., Oomens, J., Buma, W.J., Lee, T.J., Tielens, A.G.G.M., Mackie, C.J., Candian, A., Huang, X., Maltseva, E., Petrignani, A., Oomens, J., Buma, W.J., Lee, T.J., and Tielens, A.G.G.M.

Abstract

Contains fulltext : 182973.pdf (publisher's version ) (Open Access)

Published
2017

40. Photoionization and photodissociation dynamics of H[sub 2] after (3+1) resonance-enhanced....

Author

Scheper, C.R. and Buma, W.J.

Subjects
*PHOTOIONIZATION of gases, *PHOTODISSOCIATION, *HYDROGEN
Abstract

Examines photoionization and photodissociation processes of molecular hydrogen using the resonance-enhanced multiphoton ionization with photoelectron spectroscopy. Background on several dissociative recombination studies; Analysis of photon excitation spectra; Description of photoionization and photodissociation observed.

Published
1998
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41. Rotationally resolved multiphoton ionization photoelectron spectroscopy...

Author

Milan, J.B., Buma, W.J., de Lange, A., Wamg, Kwanghsi, and McKoy, V.

Subjects
*PHOTOELECTRONS, *RYDBERG states, *THIOLS
Abstract

Presents experimental and theoretical results on rotationally resolved photoelectron spectra of Rydberg states of the mercapto radical (SH). Ionization via a large number of members of different rotational branches; Asymmetries in rotational ionic distributions; Suppression of transitions involving a large change in angular momentum.

Published
1997
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42. Resonance-enhanced multiphoton-ionization photoelectron spectroscopy of even-parity autoionizing...

Author

Woutersen, S., Milan, J.B., Buma, W.J., and de Lange, C.A.

Subjects
RESONANCE, AUGER effect, RYDBERG states
Abstract

Examines the resonance-enhanced multiphoton-ionization photoelectron spectroscopy of even-parity autoionizing Rydberg states of atomic sulphur. Relative magnitudes of the one-photon absorption and autoionization rates of excited states; Signal-to-noise ratios in the two-photon energy region. .

Published
1997
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43. High-resolution IR Absorption Spectroscopy of Polycyclic Aromatic Hydrocarbons in the 3 μm Region: Role of Periphery

Author

Maltseva, E., Petrignani, A., Candian, A., Mackie, C.J., Huang, X., Lee, T.J., Tielens, A.G.G.M., Oomens, J., Buma, W.J., Maltseva, E., Petrignani, A., Candian, A., Mackie, C.J., Huang, X., Lee, T.J., Tielens, A.G.G.M., Oomens, J., and Buma, W.J.

Abstract

Contains fulltext : 166299.pdf (preprint version ) (Open Access), In this work we report on high-resolution IR absorption studies that provide a detailed view on how the peripheral structure of irregular polycyclic aromatic hydrocarbons (PAHs) affects the shape and position of their 3 μ m absorption band. For this purpose, we present mass-selected, high-resolution absorption spectra of cold and isolated phenanthrene, pyrene, benz[a]antracene, chrysene, triphenylene, and perylene molecules in the 2950–3150 cm −1 range. The experimental spectra are compared with standard harmonic calculations and anharmonic calculations using a modified version of the SPECTRO program that incorporates a Fermi resonance treatment utilizing intensity redistribution. We show that the 3 μ m region is dominated by the effects of anharmonicity, resulting in many more bands than would have been expected in a purely harmonic approximation. Importantly, we find that anharmonic spectra as calculated by SPECTRO are in good agreement with the experimental spectra. Together with previously reported high-resolution spectra of linear acenes, the present spectra provide us with an extensive data set of spectra of PAHs with a varying number of aromatic rings, with geometries that range from open to highly condensed structures, and featuring CH groups in all possible edge configurations. We discuss the astrophysical implications of the comparison of these spectra on the interpretation of the appearance of the aromatic infrared 3 μ m band, and on features such as the two-component emission character of this band and the 3 μ m emission plateau.

Published
2016

45. Water Dissociation upon Adsorption onto Free Iron Clusters Is Size Dependent

Author

Kiawi, D.M.N.A., Chernyy, V., Oomens, J., Buma, W.J., Jamshidi, Z., Visscher, L., Waters, L., Bakker, J.M., Kiawi, D.M.N.A., Chernyy, V., Oomens, J., Buma, W.J., Jamshidi, Z., Visscher, L., Waters, L., and Bakker, J.M.

Abstract

Contains fulltext : 159966pos.pdf (postprint version ) (Open Access) Contains fulltext : 159966.pdf (publisher's version ) (Closed access)

Published
2016

46. The anharmonic quartic force field infrared spectra of five non-linear polycyclic aromatic hydrocarbons: Benz[a]anthracene, chrysene, phenanthrene, pyrene, and triphenylene

Author

Mackie, C.J., Candian, A., Huang, X.C., Maltseva, E., Petrignani, A., Oomens, J., Mattioda, A.L., Buma, W.J., Lee, T.J., Tielens, A., Mackie, C.J., Candian, A., Huang, X.C., Maltseva, E., Petrignani, A., Oomens, J., Mattioda, A.L., Buma, W.J., Lee, T.J., and Tielens, A.

Abstract

Contains fulltext : 161536.pdf (publisher's version ) (Open Access)

Published
2016

49. Water Adsorption on Free Cobalt Cluster Cations

Author

Kiawi, D.M.N.A., Bakker, J.M., Oomens, J., Buma, W.J., Jamshidi, Z., Visscher, L., Waters, L.B.F.M., Kiawi, D.M.N.A., Bakker, J.M., Oomens, J., Buma, W.J., Jamshidi, Z., Visscher, L., and Waters, L.B.F.M.

Abstract

Contains fulltext : 150121pos.pdf (postprint version ) (Open Access)

Published
2015

50. Resonance enhanced multiphoton ionisation spectroscopy of carbonyl sulphide

Author

Morgan, R.A., Baldwin, M.A., Orr-Ewing, A.J., Ascenzi, D., Ashfold, M.N.R., Buma, W.J., Scheper, C.R., de Lange, C.A., and HIMS former research (FNWI)

Subjects
Resonance-enhanced multiphoton ionization, Chemistry, General Physics and Astronomy, Resonance, Quantum defect, symbols.namesake, Ionization, Excited state, Rydberg atom, Rydberg formula, symbols, Physical and Theoretical Chemistry, Atomic physics, Spectroscopy
Abstract

Rydberg excited states of the OCS molecule in the energy range 70500–86000 cm−1 have been investigated via the two and three photon resonance enhancements they provide in the mass resolved multiphoton ionization (MPI) spectrum of a jet‐cooled sample of the parent molecule. Spectral interpretation has been assisted by companion measurements of the kinetic energies of the photoelectrons that accompany the various MPI resonances. The present study supports the earlier conclusions of Weinkauf and Boesl [J. Chem. Phys. 98, 4459 (1993)] regarding five Rydberg origins in the 70500–73000 cm−1 energy range, attributable to, respectively, states of 3Π, 1Π, 3Δ, 1Δ and 1Σ+ symmetry arising from the 4pλ←3π orbital promotion. We also identify a further 21 Rydberg origins at higher energies. These partition into clumps with quantum defects ca. 3.5 and 4.5, which we associate with the orbital promotions npλ←3π (n=5,6), and others with near integer quantum defect which are interpretable in terms of excitation to s,d and (...

Published
1996
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