Synopsis

Computes the excess exchange chemical potential for alchemical semi-grand ensemble.

This quantity calculates the average of the Boltzmann weight exp(-delE/ kT) associated with the change delE in nonbonded pair potential energy caused by a hypothetical "alchemical" change of the atom types for atoms within molecules of a specified species. The transformation is defined by specifying new atom type ids for all atoms in molecules of this species, some of which may be identical to the existing atom types.

See also: McMd::McMuExchange

Parameters

The parameter file format is:

McMuExchange{
  interval           int
  outputFileName     string
  speciesId          int
  newTypeIds         DArray<int>
}

in which

interval	number of steps between data samples
outputFileName	name of output file
nSamplePerBlock	number of samples per block average
speciesId	integer index of molecule species
newTypeIds	Array of new integer type ids for all atoms after transformation. The number of elements must equal the number of atoms per molecule in species speciesId

Output

During the simulation, if nSamplePerBlock > 0, block averages are output to the file {outputFileName}.dat. If nSamplePerBlock == 0, this file is not created.

At the end of the simulation:

parameters are echoed to file {outputFileName}.prm
the average and error analysis info are output to {outputFileName}.ave