Molden allows the calculation of charges fitted to the ElectroStatic Potential (ESP) on a series of connolly surfaces. (gamess/gaussian only). EXAMPLE:
molden esp.test > esp.outWhere the contents of the file esp.test would be:
esp test file = gaussian.test espch ptden=4.0 debugRelevant keywords are:
KEYWORDS: Default ESPCH triggers calculation esp charges NUMSURF=n the number of connolly surfaces (4) CONNSC=n.n initial scalefactor vdwaals radii (1.4) CONNINCR=n.n increment scalefactor for next surface (0.2) PTDEN=n.n Density of points per Unit Area (3.0) ARESP Write out input files for the aresp program ISODEN=(isoval1,isoval2,isoval3) ISODEN Fit the electrostatic potential on (3) isodensity surfaces DIPX=n.n specifies dipole moment to be fitted to DIPY=n.n specifies dipole moment to be fitted to DIPZ=n.n specifies dipole moment to be fitted to The default is not to fit the dipole moment When constructing the atomspheres which make up the connolly surface, use as principle axis : (sometimes necessary when you want to reproduce symmetry) AXIS-X,AXIS-Y,AXIS-Z AXIS-Z After the calculation a file called "esp.xyz" is created, which can be read in by molden and charges can be displayed by clicking the label button.
After BESLER,MERZ,KOLLMAN J. COMPUT. CHEM. 11: 431-439; 1990
RESP is a program that will let you fit charges to multiple conformations. Resp is part of the antechamber suite of programs Download it here. When using the keyword ARESP molden will write out the resp input files: esp.in (containing the electrostatic potential) and resp.in (the resp keyword file) NOTE: Gaussian users not should forget to add the 6D gaussian input keyword to the gaussian input file.