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April 11, 2021

Dint - version 2.0
Direct Nonadiabatic Trajectories: A code for non-Born-Oppenheimer molecular dynamics

Ahren W. Jasper
Argonne National Laboratory

Rui Ming Zhang
Tsinghua University
University of Minnesota

and Donald G. Truhlar
University of Minnesota

Dint status:

Most recent version: 2.0
Date of most recent version: December 10, 2020
Date of most recent manual update: July 16, 2021


Dint is a parallel Fortran computer program for performing classical and semiclassical trajectory simulations of electronically adiabatic and nonadiabatic processes. Dint - version 2.0 can be used for dynamics governed either by a single potential energy surface (electronically adiabatic processes) or by two or more coupled potential energy surfaces (electronically nonadiabatic processes). Dint - version 2.0 can handle reactive trajectories, bimolecular inelastic collisions, and unimolecular processes. Dint - version 2.0 can be run at fixed energy or for thermal ensembles. Dint - version 2.0 can also perpare initial conditions of a molecule according to a fixed-energy microcanonical ensemble.

Features of Dint - version 2.0:

1. Adiabatic dynamics:
One can run ensembles of single-surface classical trajectories using either a user-supplied analytic potential energy surface or via direct calls to the electronic structure programs Gaussian and Molpro.

2. Nonadiabatic dynamics:
One can run ensembles of coupled multi-state semiclassical trajectories using a user-supplied analytic diabatic potential energy matrix (DPEM) or via direct calls to the electronic structure programs Gaussian and Molpro. Several semiclassical non-Born-Oppenheimer (multi-state) trajectory methods are available, including:
  • Decay-of-mixing methods
    Coherent Switches with Decay of Mixing (CSDM) [J. Chem. Phys. 121, 7658 (2004); J. Chem. Theor. Comput. 1, 527 (2005)].
    Self Consistent Decay of Mixing (SCDM) [J. Chem. Phys. 120, 5543 (2004)].
  • Mean field methods
    Semiclassical Ehrenfest (SE, aka TDSCF) [J. Chem. Phys. 70, 3214 (1979); J. Chem. Phys. 109, 3321 (1998)].
  • Surface hopping methods
    Fewest Switches with Time Uncertainty (FSTU) [J. Chem. Phys. 116 (02), 5424 (2002); Chem. Phys. Lett. 369 (03), 60 (2003)].
    FSTU with stochastic decoherence (FSTU/SD) [J. Chem. Phys. 127, 194306 (2007)].
    Tully's Fewest Switches (TFS) [J. Chem. Phys. 93, 1061 (1990)].

    3. Initial conditions:
  • Quasiclassical state selection
  • Classical thermal ensembles
  • Microcanonical ensembles
  • User-supplied initial conditions

    4. Parallelization:
    The code may be compiled using an MPI compiler and run in parallel. Parallel runs evenly distribute trajectories among available resources.
    Potential energy surfaces and coupling surfaces

    5. Potential energy surfaces and coupling surfaces
    For single-surface dynamics, the user must supply a subroutine that calculates the potential energy surface and its gradient, or the user must provide an input file template for Gaussian or Molpro. For multi-state dynamics, the user must supply one of the following:
    (1) a subroutine that returns the DPEM and the gradients of its elements,
    (2) a subroutine that returns the adiabatic potential energies, their gradients, and their vector couplings,
    or (3) a template input file or files for Gaussian or Molpro.
    If a DPEM is supplied, whether via an analytic surface of via calls to Gaussian or Molpro, the semiclassical dynamics can be carried out in either the diabatic or adiabatic representations. If adiabatic potential energy surfaces and couplings are supplied, whether via analytic surfaces or via calls to Molpro, the semiclassical dynamics must be carried out in the adiabatic representation. A variety of sample potential energy surface subroutines are distributed with the code and more are available in the POTLIB library (https://comp.chem.umn.edu/potlib/).

    Platform compatibility of Dint - version 2.0:

    The DiNT code has been tested successfully on the CentOS Linux with Intel MPI FORTRAN Compiler 2017

    Users' Manual:
    Dint - version 2.0 Users' Manual in PDF form

    Dint - version 2.0 is licensed under the Apache License, Version 2.0.
    The manual of Dint - version 2.0 is licensed under CC-BY-4.0.

    Publications of results obtained with Dint - version 2.0 software should cite the program [1]. Optionally one should also cite the book chapter [2] that explains many of the methods used in the program.

    No guarantee is made that this software is bug-free or suitable for specific applications, and no liability is accepted for any limitations in the mathematical methods and algorithms used within. No consulting or maintenance services are guaranteed or implied.

    The use of the Dint - version 2.0 implies acceptance of the terms of the licenses. The software may be downloaded here.

    [1] Ahren W. Jasper, Rui Ming Zhang and Donald G. Truhlar, Dint version - 2.0, 2020, https://comp.chem.umn.edu/dint
    [2] Non-Born-Oppenheimer molecular dynamics for conical intersections, avoided crossings, and weak interactions. A. W. Jasper and D. G. Truhlar, in Conical Intersections: Theory, Computation, and Experiment, edited by W. Domcke, D. R. Yarkony, and H. Koppel (World Scientific, Singapore, 2011), pp. 375–412. DOI:10.1142/9789814313452_0010


    Our research is supported in part by the U.S. Department of Energy, Office of Basic Energy Sciences.

    To obtain Dint - version 2.0:

    Downloading the program affirms agreement with the Apache License, Version 2.0. and the CC-BY-4.0 license and agreement to cite the program and optionally the book chapter about the program if you publish results based on the program.
    Download Dint - version 2.0.

    Links to other pages of interest:

    This document last modified on Oct. 20, 2022
    Updated by:  Software Manager