Collisional Energy Transfer Probability Densities P(E, J; E′ J′) for Monatomics Colliding with Large Molecules

被引:48
作者
Barker, John R. [1 ]
Weston, Ralph E., Jr. [2 ]
机构
[1] Univ Michigan, Ann Arbor, MI 48109 USA
[2] Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA
基金
美国国家科学基金会;
关键词
VIBRATIONALLY EXCITED PYRAZINE; CLASSICAL TRAJECTORY SIMULATIONS; THERMAL UNIMOLECULAR REACTIONS; RADICAL RECOMBINATION KINETICS; 2-DIMENSIONAL MASTER EQUATION; LARGE POLYATOMIC-MOLECULES; SELECTIVE IONIZATION KCSI; DER-WAALS CLUSTERS; LOW-PRESSURE-LIMIT; CHEMICAL-REACTIONS;
D O I
10.1021/jp106443d
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Collisional energy transfer remains an important area of uncertainty in master equation simulations. Quasi-classical trajectory (QCT) calculations were used to examine the energy transfer probability density distribution (energy transfer kernel), which depends on translational temperature, on the nature of the collision partners, and on the initial and final total internal energies and angular momenta: P(E, J; E', J'). For this purpose, model potential energy functions were taken from the literature or were formulated for pyrazine + Ar and for ethane + Ar collisions. For each collision pair, batches of 10(5) trajectories were computed with three selected initial vibrational energies and five selected values for initial total angular momentum. Most trajectories were carried out with relative translational energy distributions at 300 K, but some were carried out at 1000 or 1200 K. In addition, some trajectories were computed for artificially "heavy" ethane, in which the H-atoms were assigned masses of 20 amu. The results were binned according to (Delta E, Delta J), and a least-squares analysis was carried out by omitting the quasi-elastic trajectories from consideration. By trial-and-error, an empirical function was identified that fitted all 45 batches of trajectories with moderate accuracy. The results reveal significant correlations between initial and final energies and angular momenta. In particular, a strong correlation between Delta E and Delta J depends on the smallest rotational constant in the excited polyatomic. These results show that the final rotational energy distribution is not independent of the initial distribution, showing that the plausible simplifying assumption described by Smith and Gilbert [Int. J. Chem. Kinet. 1988, 20, 307-329] and extended by Miller, Klippenstein, and Rally [J. Phys. Chem. A 2002, 106, 4904-4913] is invalid for the systems studied.
引用
收藏
页码:10619 / 10633
页数:15
相关论文
共 135 条
[1]  
ALEXANDER WA, 2008, J CHEM PHYS, P128
[2]   Theoretical study of the Ar-, Kr-, and Xe-CH4, -CF4 intermolecular potential-energy surfaces [J].
Alexander, William A. ;
Troya, Diego .
JOURNAL OF PHYSICAL CHEMISTRY A, 2006, 110 (37) :10834-10843
[3]   ROLE OF ANGULAR-MOMENTUM IN STATISTICAL UNIMOLECULAR RATE THEORY [J].
AUBANEL, EE ;
WARDLAW, DM ;
ZHU, L ;
HASE, WL .
INTERNATIONAL REVIEWS IN PHYSICAL CHEMISTRY, 1991, 10 (03) :249-286
[5]   Vibrational energy transfer modeling of nonequilibrium polyatomic reaction systems [J].
Barker, JR ;
Yoder, LM ;
King, KD .
JOURNAL OF PHYSICAL CHEMISTRY A, 2001, 105 (05) :796-809
[6]   Multiple-well, multiple-path unimolecular reaction systems. I. MultiWell computer program suite [J].
Barker, JR .
INTERNATIONAL JOURNAL OF CHEMICAL KINETICS, 2001, 33 (04) :232-245
[7]   Energy transfer between polyatomic molecules II:: Energy transfer quantities and probability density functions in benzene, toluene, p-xylene, and azulene collisions [J].
Bernshtein, V ;
Oref, I .
JOURNAL OF PHYSICAL CHEMISTRY A, 2006, 110 (04) :1541-1551
[8]   EFFECT OF SUPERCOLLISIONS ON CHEMICAL-REACTIONS IN THE GAS-PHASE [J].
BERNSHTEIN, V ;
OREF, I .
JOURNAL OF PHYSICAL CHEMISTRY, 1993, 97 (49) :12811-12818
[9]   Energy transfer rate coefficients from trajectory calculations and contributions of supercollisions to reactive rate coefficients [J].
Bernshtein, V ;
Oref, I ;
Lendvay, G .
JOURNAL OF PHYSICAL CHEMISTRY, 1996, 100 (23) :9738-9744
[10]   Intermolecular energy transfer probabilities from trajectory calculations: A new approach [J].
Bernshtein, V ;
Oref, I .
JOURNAL OF CHEMICAL PHYSICS, 1998, 108 (09) :3543-3553