A. Alenaizan's restricted electrostatic potential (RESP) plugin to Psi4
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alenaizan Merge pull request #3 from alenaizan/master
Allows for passing of psi4 options
Latest commit f6ed65e Sep 6, 2018


Restrained Electrostatic Potential

The following codes are available:

  • resp/espfit.py: The restrained electrostatic potential (RESP) fitting procedure.
  • resp/driver.py: Driver of the code.
  • resp/tests/test_resp.py contains:
    • test_resp_1: Example for two-stage charge fitting for one conformer.
    • test_resp_2: Example for two-stage charge fitting for two conformers.

Helper programs:

  • resp/vdw_surface_helper.py
  • resp/stage2_helper.py

RESP charges result from fitting the classical electrostatic potential (ESP) generated by atom-centered point charges to the quantum ESP computed outside the van der Waals surface of the molecule. The fitted charges are restrained by a hyperbolic term, which requires an iterative fitting procedure to compute the charges.

The charges (q) are computed by solving the following equation:

A q = B.

The left-hand side contains the information about the classical ESP while the right-hand side contains information about the quantum ESP. A hyperbolic restraint term that depends on the charges is added to the diagonal elements of matrix A. The charges and the diagonal elements of A are changed iteratively until the charges converge.