TY - JOUR
T1 - Ab initio quantum dynamical study of the multi-state nonadiabatic photodissociation of pyrrole
AU - Faraji, S.
AU - Vazdar, M.
AU - Reddy, V. Sivaranjana
AU - Eckert-Maksic, M.
AU - Lischka, H.
AU - Köppel, H.
N1 - Funding Information:
We thank various students for their most valuable help with the data analysis, M. Hess, F. Kohle, A. Komainda, V. Stumpf and L. Brückner. Financial support by the Deutsche Forschungsgemeinschaft is gratefully acknowledged. M.V. and M.E.-M. acknowledge support by the Ministry of Science, Education and Sport of Croatia through the project 098-0982933-2920. V.S.R. gratefully acknowledges the Alexander von Humboldt Stiftung for a research fellowship. The support by the COST D37 action, WG0001-06 and the WTZ treaty between Austria and Croatia (Project No. HR17/2008) and by the Robert A. Welch Foundation under Grant No. D-0005 is also acknowledged. The calculations were performed in part at the Vienna Scientific Cluster (Project Nos. 70019 and 70151) of the Vienna University Computer Centre.
PY - 2011/10/21
Y1 - 2011/10/21
N2 - There has been a substantial amount of theoretical investigations on the photodynamics of pyrrole, often relying on surface hopping techniques or, if fully quantal, confining the study to the lowest two or three singlet states. In this study we extend ab initio based quantum dynamical investigations to cover simultaneously the lowest five singlet states, two π - σ* and two π - π* excited states. The underlying potential energy surfaces are obtained from large-scale MRCI ab initio computations. These are used to extract linear and quadratic vibronic coupling constants employing the corresponding coupling models. For the N-H stretching mode Q24 an anharmonic treatment is necessary and also adopted. The results reveal a sub-picosecond internal conversion from the S4 (π - π*) state, corresponding to the strongly dipole-allowed transition, to the S 1 and S2 (π - σ* ) states and, hence, to the ground state of pyrrole. The significance of the various vibrational modes and coupling terms is assessed. Results are also presented for the dissociation probabilities on the three lowest electronic states.
AB - There has been a substantial amount of theoretical investigations on the photodynamics of pyrrole, often relying on surface hopping techniques or, if fully quantal, confining the study to the lowest two or three singlet states. In this study we extend ab initio based quantum dynamical investigations to cover simultaneously the lowest five singlet states, two π - σ* and two π - π* excited states. The underlying potential energy surfaces are obtained from large-scale MRCI ab initio computations. These are used to extract linear and quadratic vibronic coupling constants employing the corresponding coupling models. For the N-H stretching mode Q24 an anharmonic treatment is necessary and also adopted. The results reveal a sub-picosecond internal conversion from the S4 (π - π*) state, corresponding to the strongly dipole-allowed transition, to the S 1 and S2 (π - σ* ) states and, hence, to the ground state of pyrrole. The significance of the various vibrational modes and coupling terms is assessed. Results are also presented for the dissociation probabilities on the three lowest electronic states.
UR - http://www.scopus.com/inward/record.url?scp=80155147806&partnerID=8YFLogxK
U2 - 10.1063/1.3651536
DO - 10.1063/1.3651536
M3 - Article
C2 - 22029316
AN - SCOPUS:80155147806
VL - 135
JO - The Journal of Chemical Physics
JF - The Journal of Chemical Physics
SN - 0021-9606
IS - 15
M1 - 154310
ER -