Abstract
A generalized cumulant expansion method is developed for applying stochastic reductions to molecular collision processes. We begin by introducing an approximate partitioning of a collision system into two subsystems S r and Si which are assumed to be weakly correlated. Cumulant expansion methods are then used to simultaneously perform a stochastic reduction over Si, and a projection of the diagonal elements of the reduced density matrix for Sr thereby leading to a Pauli master equation describing Sr. We then apply this general equation using an impulse approximation partitioning to problems in inelastic V-T and R-T scattering. For He+ H2 vibrationally inelastic collisions, the stochastic theory predicts low order moments and some probabilities in very good agreement with exact quantum results. In applications to He+ H2 rigid rotor scattering, integral cross sections and opacity functions within 10%-30% of exact results are obtained at most energies.
| Original language | English |
|---|---|
| Pages (from-to) | 5220-5225 |
| Number of pages | 6 |
| Journal | Journal of Chemical Physics |
| Volume | 66 |
| Issue number | 11 |
| Publication status | Published - 1977 |
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ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
Cite this
The generalized cumulant expansion approach to stochastic reductions in molecular collision dynamics : Applications to collisional energy transfer. / Schatz, George C.
In: Journal of Chemical Physics, Vol. 66, No. 11, 1977, p. 5220-5225.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The generalized cumulant expansion approach to stochastic reductions in molecular collision dynamics
T2 - Applications to collisional energy transfer
AU - Schatz, George C
PY - 1977
Y1 - 1977
N2 - A generalized cumulant expansion method is developed for applying stochastic reductions to molecular collision processes. We begin by introducing an approximate partitioning of a collision system into two subsystems S r and Si which are assumed to be weakly correlated. Cumulant expansion methods are then used to simultaneously perform a stochastic reduction over Si, and a projection of the diagonal elements of the reduced density matrix for Sr thereby leading to a Pauli master equation describing Sr. We then apply this general equation using an impulse approximation partitioning to problems in inelastic V-T and R-T scattering. For He+ H2 vibrationally inelastic collisions, the stochastic theory predicts low order moments and some probabilities in very good agreement with exact quantum results. In applications to He+ H2 rigid rotor scattering, integral cross sections and opacity functions within 10%-30% of exact results are obtained at most energies.
AB - A generalized cumulant expansion method is developed for applying stochastic reductions to molecular collision processes. We begin by introducing an approximate partitioning of a collision system into two subsystems S r and Si which are assumed to be weakly correlated. Cumulant expansion methods are then used to simultaneously perform a stochastic reduction over Si, and a projection of the diagonal elements of the reduced density matrix for Sr thereby leading to a Pauli master equation describing Sr. We then apply this general equation using an impulse approximation partitioning to problems in inelastic V-T and R-T scattering. For He+ H2 vibrationally inelastic collisions, the stochastic theory predicts low order moments and some probabilities in very good agreement with exact quantum results. In applications to He+ H2 rigid rotor scattering, integral cross sections and opacity functions within 10%-30% of exact results are obtained at most energies.
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M3 - Article
VL - 66
SP - 5220
EP - 5225
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
SN - 0021-9606
IS - 11
ER -