The OH + D2→ HOD + D angle–velocity distribution: quasi-classical trajectory calculations on the YZCL2 and WSLFH potential energy surfaces and comparison with experiments at ET = 0.28 eV

Abstract

The angle-velocity distribution (HOD) of the OH + D(2) reaction at a relative translational energy of 0.28 eV has been calculated using the quasi-classical trajectory (QCT) method on the two most recent potential energy surfaces available (YZCL2 and WSLFH PESs), widely extending a previous investigation of our group. Comparison with the high resolution experiments of Davis and co-workers (Science, 2000, 290, 958) shows that the structures (peaks) found in the relative translational energy distributions of products could not be satisfactorily reproduced in the calculations, probably due to the classical nature of the QCT method and the importance of quantum effects. The calculations, however, worked quite well for other properties. Overall, both surfaces led to similar results, although the YZCL2 surface is more accurate to describe the H(3)O PES, as derived from comparison with high level ab initio results. The differences observed in the QCT calculations were interpreted considering the somewhat larger anisotropy of the YZCL2 PES when compared with the WSLFH PES.

The method of Gaussian weighted trajectories. V. On the 1GB procedure for polyatomic processes

“…On the other hand, the distribution obtained from Eqs. (42), (43) and (45), also shown in Fig. 4 (1GB' curve), has the good shape, but its norm is too large.…”

“…The predictions to which it leads are compared in section III with the usual SB and GB predictions for a model test case involving three vibrational modes. In section IV, the approach is applied to the prototype four-body chemical reaction OH+D 2 −→ HOD+D which is among the simplest polyatomic bimolecular reactions [38][39][40][41][42][43][44]. We finally conclude in section V.…”

Low-energy inelastic collisions of OH radicals with He atoms andD2molecules

“…In crossed beam experiments, inelastic as well as reactive scattering processes have been studied at high collision energies [27][28][29]. The system has recently been treated theoretically using the quasiclassical trajectory method [30]. Rotational inelastic cross sections for the related OH-H 2 system have been calculated by Van Dishoeck and co-workers [31].…”

Classical versus quantum vibrational state distributions for the benchmark polyatomic reaction OH+D2: Checking the validity of the QCT method

“…HOD + D is a benchmark polyatomic bimolecular reaction [2][3][4][5][6][7][8][9][10][11]. It is the analogue of F + H 2 ?…”

“…So, this PES represents an excellent opportunity to test the validity of the QCT method, as compared with AQS and EQS calculations. When in the QCT calculations the standard binning (SB) procedure (which amounts to attribute the same statistical weight to each trajectory) was used, the experimental product vibrational state populations were not reproduced [6][7][8][9]. However, using the Gaussian binning (GB) procedure, which takes into account Bohr quantization principle for vibrational energies [17][18][19][20][21][22][23][24][25][26][27][28], made the expected product state spectrum appear, for the first time as far as polyatomic processes are concerned [10].…”