TY - JOUR
T1 - Optimization of mixed quantum-classical dynamics
T2 - Time-derivative coupling terms and selected couplings
AU - Pittner, Jiri
AU - Lischka, Hans
AU - Barbatti, Mario
N1 - Funding Information:
This work was supported by the Austrian Science Fund within the framework of the Special Research Program F16 (Advanced Light Sources) and Project No. IAA400400810 of the Granting Agency of the Academy of Sciences of Czech Republic. The authors are grateful for technical support and computer time at the Linux PC cluster Schrödinger III of the computer center of the University of Vienna.
PY - 2009/2/17
Y1 - 2009/2/17
N2 - The usage of time-derivative non-adiabatic coupling terms and partially coupled time-dependent equations are investigated to accelerate non-adiabatic dynamics simulations at multireference configuration interaction (MRCI) level. The quality of the results and computational costs are compared against non-adiabatic benchmark dynamics calculations using non-adiabatic coupling vectors. In the comparison between the time-derivative couplings and coupling vectors, deviations in the adiabatic population of individual trajectories were observed in regions of rapid variation of the coupling terms. They, however, affected the average adiabatic population to only about 5%. For small multiconfiguration spaces, dynamics with time-derivative couplings are significantly faster than those with coupling vectors. This relation inverts for larger configuration spaces. The use of the partially coupled equations approach speeds up the simulations significantly while keeping the deviations in the population below few percent. Imidazole and the methaniminium cation are used as test examples.
AB - The usage of time-derivative non-adiabatic coupling terms and partially coupled time-dependent equations are investigated to accelerate non-adiabatic dynamics simulations at multireference configuration interaction (MRCI) level. The quality of the results and computational costs are compared against non-adiabatic benchmark dynamics calculations using non-adiabatic coupling vectors. In the comparison between the time-derivative couplings and coupling vectors, deviations in the adiabatic population of individual trajectories were observed in regions of rapid variation of the coupling terms. They, however, affected the average adiabatic population to only about 5%. For small multiconfiguration spaces, dynamics with time-derivative couplings are significantly faster than those with coupling vectors. This relation inverts for larger configuration spaces. The use of the partially coupled equations approach speeds up the simulations significantly while keeping the deviations in the population below few percent. Imidazole and the methaniminium cation are used as test examples.
KW - Mixed-quantum classical dynamics
KW - Non-adiabatic coupling
UR - http://www.scopus.com/inward/record.url?scp=59349094466&partnerID=8YFLogxK
U2 - 10.1016/j.chemphys.2008.10.013
DO - 10.1016/j.chemphys.2008.10.013
M3 - Article
AN - SCOPUS:59349094466
SN - 0301-0104
VL - 356
SP - 147
EP - 152
JO - Chemical Physics
JF - Chemical Physics
IS - 1-3
ER -