Application of the Interaction Picture to Reactive Scattering in One Dimension.
Abstract
The interaction picture is used together with the channel-packet method in a new time-dependent approach to compute reactive scattering matrix elements. The channel-packet method enables the use of the interaction picture for computing reactive S-matrix elements by splitting the computational effort into two parts. First, asymptotic reactant and product wavepackets are individually propagated into the interaction region of the po tential to form Moeller states. The interaction picture, in contrast to the usual Schroedinger picture of quantum mechanics, is so constructed that a wavefunction that experiences no change in potential (that is, a free-particle wavefunction) remains always hxed, with no translation or distortion. In the Schro%dinger picture, free-particle wavefunctions translate and spread with time. By removing free-particle spreading, the use of the interaction picture reduces the size of the region of space that must be modeled when computing the Moeller states. Since the asymptotic wavepackets are propagated in time independently of each other, it is possible to choose an asymptotic llamiltonian and corresponding interaction picture that is well suited for each arrangement channel. By using two different interaction pictures, one for the reactant arrangement channel and one for the product arrangement channel, it is possible to realize savings in the required grid size. During the second part of the channel-packet computation, the reactant and product wavepackets oh tained from the first part of the calculation are further propagated using the Schroedinger picture. The tim&dependent correlation between the evolving wavepackets is calculated as they split into energetically accessible arrangement channels and are absorbed using absorbing boundary conditions.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 09, 1999
- Accession Number
- ADA368061
Entities
People
- Michael J. Maclachlan
Organizations
- Air Force Institute of Technology