TY - JOUR

T1 - Multiconfiguration time-dependent self-consistent field approximations in the numerical solution of quantum dynamical problems

AU - Kotler, Zvi

AU - Neria, Eyal

AU - Nitzan, Abraham

N1 - Funding Information:
This research was partially supported by the Israel Academy of science and by the USA—Israel Binational Science Foundation. We thank Professor R. Kosloff for very helpful discussions.

PY - 1991/2

Y1 - 1991/2

N2 - The use of the time-dependent self-consistent field approximation (TDSCF) in the numerical solution of quantum curve crossing and tunneling dynamical problems is investigated. Particular emphasis is given to multiconfiguration TDSCF (MCTDSCF) approximations, which are shown to perform considerably better with only a small increase in computational effort. We investigate a number of simple models in which a "system" characterized by two electronic potential surfaces evolves while interacting with a "bath" mode described by an harmonic oscillator, and compare exact numerical solutions to one- and two-configuration TDSCF approximations. We also introduce and investigate a semiclassical approximation in which the "bath" mode is described by semiclassical wavepackets (one for each electronic state) and show that for all models investigated this scheme works very well in comparison with the fully quantum MCTDSCF approximation. This provides a potentially very useful method to simulate strongly quantum systems coupled to an essentially classical environment.

AB - The use of the time-dependent self-consistent field approximation (TDSCF) in the numerical solution of quantum curve crossing and tunneling dynamical problems is investigated. Particular emphasis is given to multiconfiguration TDSCF (MCTDSCF) approximations, which are shown to perform considerably better with only a small increase in computational effort. We investigate a number of simple models in which a "system" characterized by two electronic potential surfaces evolves while interacting with a "bath" mode described by an harmonic oscillator, and compare exact numerical solutions to one- and two-configuration TDSCF approximations. We also introduce and investigate a semiclassical approximation in which the "bath" mode is described by semiclassical wavepackets (one for each electronic state) and show that for all models investigated this scheme works very well in comparison with the fully quantum MCTDSCF approximation. This provides a potentially very useful method to simulate strongly quantum systems coupled to an essentially classical environment.

UR - http://www.scopus.com/inward/record.url?scp=0026106391&partnerID=8YFLogxK

U2 - 10.1016/0010-4655(91)90253-H

DO - 10.1016/0010-4655(91)90253-H

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AN - SCOPUS:0026106391

SN - 0010-4655

VL - 63

SP - 243

EP - 258

JO - Computer Physics Communications

JF - Computer Physics Communications

IS - 1-3

ER -