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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/

https://github.com/QuantumDynamicsLab/PES2MP_ipynb

Contact: [email protected]

PES2MP (Potential Energy Surface Mapping to Multipole Expansion Series)

Multipole expansion

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:[email protected])

File 1: 2D_multipole_inv.ipynb

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}
}

File 2: Use 4D_SF_expansion.ipynb

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}
}