MoRiBS-PIMC: A program to simulate molecular rotors in bosonic solvents using path-integral Monte Carlo

Abstract

We provide the source code of our in-house program MoRiBS-PIMC. This program was developed to simulate rigid molecules rotating in bosonic clusters composed of helium atoms, parahydrogen molecules or any other bosonic point solvent particles. The program can be employed to obtain superfluid response, structural and energetic properties as well as imaginary time correlation functions of dipole operators. These quantities can be used to interpret and predict the results of spectroscopic Andronikashvili experiments. The software is based on the latest advances in the simulation of the quantum rotation of non-linear rigid rotors and in the sampling of bosonic permutations. The program has been parallelized to improve its performance and new techniques have been implemented to obtain symmetry-adapted simulation results. The usage and robustness of the program is demonstrated with some illustrative examples. Program summaryProgram title: MoRiBS-PIMCCatalogue identifier: AFAD_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AFAD_v1_0.htmlProgram obtainable from: CPC Program Library, Queen’s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 4161981No. of bytes in distributed program, including test data, etc.: 25399583Distribution format: tar.gzProgramming language: C++ and Fortran77.Computer: Any computers with OpenMP libraries installed.Operating system: Linux.RAM: On the order of hundreds of MBytes and system-dependent. See Section 5 for examples.Supplementary material: The full input data for the examples is available for download.Classification: 16.02, 16.10, 16.13, 23.External routines: Lapack routine, dsyev, is needed in a subprogram asymrho.f. Dynamic library for quadruple precision floating number arithmetics is needed for subprograms asymrho.f and symrho.f and linden.f to tabulate rotational propagator, energy and heat capacity estimator. The source codes of these programs are distributed with the main program.Nature of problem: Many body quantum physics, rigid-body rotation, atomic and molecular clusters, bosonic exchange and superfluiditySolution method: Path-integral Monte Carlo simulations and worm algorithm for permutation samplingRestrictions: See Section 1 of the manuscript for details.Unusual features: This is the first program that combines the worm algorithm for bosonic permutation sampling and general rigid-body rotation for asymmetric tops. The program has extensive applications in quantum molecular dynamics and it has been parallelized via OpenMP.Additional comments: The program can be used to interpret and predict spectroscopic Andronikashvili experiments conducted on microscopic superfluids.Running time: System dependent. See Section 5 for examples.