TY  - JOUR
A1  - Kenfack, A.
A1  - Banerjee, Shiladitya
A1  - Paulus, Beate
T1  - Probing electron correlation in molecules via quantum fluxes
JF  - Physical review : A, Atomic, molecular, and optical physics
N2  - We present quantum simulations of a vibrating hydrogen molecule H-2 and address the issue of electron correlation. After appropriately setting the frame and the observer plane, we were able to determine precisely the number of electrons and nuclei which actually flow by evaluating electronic and nuclear fluxes. This calculation is repeated for three levels of quantum chemistry, for which we account for no correlation, Hartree-Fock, static correlation, and dynamic correlation. Exciting each of these systems with the same amount of energy, we show that the electron correlation can be revealed with the knowledge of quantum fluxes. This is evidenced by a clear sensitivity of these fluxes to electron correlation. In particular, we find that this correlation remarkably enhances more electronic yield than the nuclear one. It turns out that less electrons accompany the nuclei in Hartree-Fock than in the correlation cases.
Y1  - 2012
U6  - https://doi.org/10.1103/PhysRevA.85.032501
SN  - 1050-2947
VL  - 85
IS  - 3
PB  - American Physical Society
CY  - College Park
ER  - 
TY  - JOUR
A1  - Banerjee, Shiladitya
A1  - Kröner, Dominik
A1  - Saalfrank, Peter
T1  - Resonance Raman and vibronic absorption spectra with Duschinsky rotation from a time-dependent perspective application to beta-carotene
JF  - The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr
N2  - The time-dependent approach to electronic spectroscopy, as popularized by Heller and co-workers in the 1980s, is applied here in conjunction with linear-response, time-dependent density functional theory to study vibronic absorption and resonance Raman spectra of beta-carotene, with and without a solvent. Two-state models, the harmonic and the Condon approximations are used in order to do so. A new code has been developed which includes excited state displacements, vibrational frequency shifts, and Duschinsky rotation, i.e., mode mixing, for both non-adiabatic spectroscopies. It is shown that Duschinsky rotation has a pronounced effect on the resonance Raman spectra of beta-carotene. In particular, it can explain a recently found anomalous behaviour of the so-called nu(1) peak in resonance Raman spectra [N. Tschirner, M. Schenderlein, K. Brose, E. Schlodder, M. A. Mroginski, C. Thomsen, and P. Hildebrandt, Phys. Chem. Chem. Phys. 11, 11471 (2009)], which shifts with the change in excitation wavelength.
Y1  - 2012
U6  - https://doi.org/10.1063/1.4748147
SN  - 0021-9606
VL  - 137
IS  - 22
PB  - American Institute of Physics
CY  - Melville
ER  -