Accounting for the dependence of P(E´,E) on the maximum impact parameter in classical trajectory calculations: Aplication to the H2O-H2O collisional relaxation

CORONADO, EDUARDO A.

JOURNAL OF CHEMICAL PHYSICS

AMER INST PHYSICS

Lugar: Melville; Año: 2007 vol. 127 p. 1543051 - 1543051

0021-9606

n this work we report a novel methodology that is able to predict how the energy tranfer probability density function P(E´,E)changes with the maximum impact parameter used in classical trajectory calculations. The method assumed that P(E´,E) can be described by a sum of exponential functions and that all the trajectories with an impact parameter beyond a certain critical value contribute only to the elastic peak . This approach is applied to water-water collisions at different vibrational energies of the excited molecules and temperatures of the bath gas. The results show that it is possible to reproduce with high accuracy the whole P(E´,E)obtained from a given maximum impact parameter using the results of trajectory calculations performed with another impact parameter. The new methodology also lead us to propose a new criterion to choose the value of the maximum impact parameter.