MADWAVE3: A quantum time dependent wave packet code for nonadiabatic state-to-state reaction dynamics of triatomic systems

Abstract

We present MADWAVE3, a FORTRAN90 code designed for quantum time-dependent wave packet propagation in triatomic systems. This program allows the calculation of state-to-state probabilities for inelastic and reactive collisions, as well as photodissociation processes, over one or multiple coupled diabatic electronic states. The code is highly parallelized using MPI and OpenMP. The execution requires the potential energy surfaces of the different electronic states involved, as well as the transition dipole moments for photodissociation processes. The formalism underlying the code is presented in section 2, together with the modular structure of the code. This is followed by the installation procedures and a comprehensive list and explanation of the parameters that control the code, organized within their respective namelists.

Finally, a case study is presented, focusing on the prototypical reactive collision H+DH($v,j$)→ H₂($v^{\prime },j^{\prime }$) + D. Both the potential energy surface and the input files required to reproduce the calculation are provided and are available on the repository's main page. This example is used to study the parallelization speedup of the code.

Program summary

Program Title: MADWAVE3

CPC Library link to program files: https://doi.org/10.17632/jv4wj2w23x.1

Developer's repository link: https://github.com/qmolastro/madwave3

Licensing provisions: GPLv3

Programming language: Fortran 90

External libraries: FFTW3, MPI

Nature of problem: Quantum time propagation of a wave packet describing a reactive process in a triatomic systems, for collisions (inelastic and reactive) and photodissociation processes, and considering several coupled diabatic electronic state

Solution method: A modified Chebyshev propagator is used, keeping the real Chebyshev components, which are represented in grids for the internal Jacobi coordinates $r,R$ and γ and in a basis for electronic and helicity components. The potential represented in a grid as well as the reactants and products wave functions are previously calculated in a preparatory stage.