pyPRISM.calculate.pair_correlation module¶

pyPRISM.calculate.pair_correlation.pair_correlation(PRISM)[source]¶

Calculate the Real-space inter-molecular pair correlation function

Parameters:	PRISM (pyPRISM.core.PRISM) – A solved PRISM object.
Returns:	pairCorr – The full MatrixArray of pair correlation functions.
Return type:	pyPRISM.core.MatrixArray

Mathematical Definition

\[g_{\alpha,\beta}(r) = h_{\alpha,\beta}(r) + 1.0\]

Variable Definitions

\(g_{\alpha,\beta}(r)\)

Pair correlation function between site types \(\alpha\) and \(\beta\) at a distance \(r\)

\(h_{\alpha,\beta}(r)\)

Total correlation function between site types \(\alpha\) and \(\beta\) at a distance \(r\)

Description

The pair correlation function describes the spatial correlations between pairs of sites in Real-space. Also known as the radial distribution function (rdf), the \(g(r)\) function is related to the underlying spatial probability distributions of a given system. In a PRISM calculation, \(g(r)\) is strictly an inter-molecular quantity.

After convergence of a PRISM object, the stored total correlation attribute function can simply be shifted to obtain the \(g(r)\)

Warning

Passing an unsolved PRISM object to this function will still produce output based on the default values of the attributes of the PRISM object.

Example

import pyPRISM

sys = pyPRISM.System(['A','B'])

# ** populate system variables **

PRISM = sys.createPRISM()

PRISM.solve()

rdf = pyPRISM.calculate.pair_correlation(PRISM)

rdf_AA = rdf['A','A']
rdf_AB = rdf['A','B']
rdf_BB = rdf['B','B']