AUTOMATED PYTHONIC VERSION CAN BE OBTAINED FROM : https://github.com/QuantumDynamicsLab/PES2MP/
UPDATED VERSION IN JUPYTER NOTEBOOK FORMAT (FOR DEBUGGING) MAY BE OBTAINED FROM : https://github.com/QuantumDynamicsLab/PES2MP_ipynb/
https://github.com/QuantumDynamicsLab/PES2MP_ipynb
Contact: dhilip@iitrpr.ac.in
2D and 4D multipole expansion code (using Legendre polynomials and Spherical Harmonics respectively) for fitting PES into radial coefficients is provided as jupyter-notebook files.
Both codes use least square fit (achieved by taking the pseudo-inverse of Legendre/Spherical-Harmonics coefficients stored in a 2D matrix).
Currently limited to rigid rotor - atom (2D) and rigid rotor - rigid rotor (4D) collision
For any queries contact Dr. T. J. Dhilip Kumar cc: (mailto:kushwaha.apoorv@gmail.com)
Uses scipy.special for Legendre coefficient
2D PES (Atom - Rigid Rotor collision)
Link: [Link to paper: See Supplementary Information]
# Bibtex citation for 2D code: multipole expansion of 2D Potential Energy Surface @article{Kushwaha2023Jan, author = {Kushwaha, Apoorv and Kumar, Thogluva Janardhanan Dhilip}, title = {{Benchmarking PES-Learn's machine learning models predicting accurate potential energy surface for quantum scattering}}, journal = {Int. J. Quantum Chem.}, volume = {123}, number = {1}, pages = {e27007}, year = {2023}, month = jan, issn = {0020-7608}, publisher = {John Wiley {\&} Sons, Ltd}, doi = {10.1002/qua.27007} }Uses pyshtools for calculating spherical harmonics (need separate installation: Instructions are provided in jupyter-notebook file)
4D PES (Two Rigid Rotors)
Link: [Link to paper: See Supplementary Information]
# Article citation for 4D code: multipole expansion of 4D Potential Energy Surface @article{Kushwaha2023Aug, author = {Kushwaha, Apoorv and Dhilip Kumar, T. J.}, title = {{4D potential energy surface of NCCN{\textendash}H2 collision: Rotational dynamics by p-H2 and o-H2 at interstellar temperatures}}, journal = {J. Chem. Phys.}, volume = {159}, number = {7}, year = {2023}, month = aug, issn = {0021-9606}, publisher = {AIP Publishing}, doi = {10.1063/5.0161335} }