Real wavepacket code for [formula omitted] reactive scattering

Abstract

We discuss a six-dimensional, time-dependent real wavepacket (RWP) code designed to obtain reaction probabilities for ABC( v I ) + D → AB + CD four-atom reactions, where v I is a collective index for the initial quantum state of the triatomic molecule. The code provides exact results for total angular momentum J = 0 , and invokes the helicity decoupling (or centrifugal sudden) approximation for J > 0 . Our new RWP code has been extensively checked by considering the benchmark H + H 2O → H 2 + OH abstraction reaction. Program summary Program title: ABC + D RWP Code Catalogue identifier: AECD_v1_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AECD_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 808 025 No. of bytes in distributed program, including test data, etc.: 4 840 859 Distribution format: tar.gz Programming language: Fortran 77 Computer: Tested on Intel Xeon 2.8 GHz; AMD Opteron 244 1.8 GHz. Should run on any architecture providing a Fortran 77 compiler. Operating system: Linux RAM: Problem dependent Classification: 16.8, 16.12 Nature of problem: Determination of dynamic properties (reaction probabilities and cross sections) for ABC + D → AB + CD four-atom reactions. Solution method: Propagation of the real part of a wavepacket under the action of a modified Hamiltonian on a grid using several techniques such as dispersion fitted finite difference and potential optimized DVR. Restrictions: Use of the helicity decoupling or centrifugal sudden approximation, which neglects the Coriolis coupling terms. Running time: Hours to days, depending on the problem under study and computational resources. The test example takes between 15 and 30 hours depending on the environment used. The example is made up of several programs and can therefore be split into shorter time periods.