Reactive Scattering on a LEPS Surface

In this Demonstration, a model potential energy surface developed by London, Eyring, Polyani, and Sato (LEPS) is used to describe the collinear

F+

H

2

H-F+H

chemical reaction. The particular parameterization is the "Muckerman V" potential. This potential surface is shown as a contour plot. The coordinates are the

F-H

and

H-H

bond lengths. The reaction proceeds with

r

F-H

being large and

R

HH

being the equilibrium bond-length of

H

2

.

The reaction path (which follows the contour minimum) connects the reactant channel to the product channel. These are separated by a saddle point that gives the configuration of the activated complex or transition state

‡

[F-H-H]

which has energy

E

b

=

-357.13 kcal/mol.

We use Newton's equations of motion to describe the collinear

F+

H

2

H-F+H

chemical reaction. The contour plot shows the Muckerman V potential describing this reaction and the thick black line is a scattering trajectory. By varying the angle

θ

, one selects how the initial kinetic energy is partitioned between the kinetic energy of the incoming fluorine atom and the vibrational kinetic energy of the

H

2

molecule. This demonstrates the influence of energy distribution amongst reactants in a given chemical reaction.