chargefit.f and points.f
Chargefit fits charges to the electrostatic potential calculated
in points around the molecule or to the electrostatic moments. The moments
or potentials are read from a gaussian (or turbomole) outputfile.
In the Gaussian calculation the IOp(6/32=3) option is used to write the potential to the output file.
The moments can be used as constraints as well as restraints. The potential points can be weighted with Boltzmann weights.
Points reads coordinates from an gaussian output file or from an other file containing atom names and coordinates (for a description of the format of this file se the program) and calculates randomly spaced points around the molecule for ESP calculation.. The maximum distance from any atom can be set to any value (we recomend 8 Angstrom). No minimal distance is needed since points with Boltsmann weights lower than 10^-6 are discarded. The result is written as a Gaussian inputfile for a ESP calculation.
The two programs points and chargefit are used for calculations of charges
according to the chelp-bow or the chelmo method described in our paper
(J. Comp. Chem. 19, 377-395, (1998)).
For the CHELMO method you use only chargefit. You need an outputfile from Gaussian with electrostatic moments calculated to be used as an input file for chargefit. Constrain to total charge and moments according to our paper.
For the CHELP-BOW you need first to run points to generate points to be used for electrostatic potential calculations. Points can read coordinates from an gaussian output file. We found this to be practical since we normally have done an energy calculation or an geometry optimisation before this calculation. Alternatively the coordinates can be read from a file with just atom names and coordinates (use for example a gaussian input file with the first lines removed). Points generates a Gaussian input file.
After running Gaussian, chargefit is to be used. This time you constrain to total charge and dipole moment according to our paper and restrain to Boltzmann weighted potential.
On our SGI machins we have compiled chargefit with f77 and it also needs
the lapack routine dgesvd. This can be fetched at: http://www.netlib.org/lapack/
Points have been compiled with f90.
The current versions of the programs work with Gaussian94.
Alternative versions of the programs
chargefit_b - handles lonepair centras (Be) slightly better (constrain them to have the same value if they are bound to the same atom and does not confuse them with heavy atoms), write some lists that Bruce are interested in and has an option of removing all points with weights less than 0.99 in the fit.
chargefit_w - special version that reads in water coordiantes and calculates the interaction energy
chargefitconf - alternative code to read in several conformations, from several gaussian files with electrostatic potentials. The comparisons to the potantial, moments etc. in the output file is not correct. If you want these comparisons run chargefit.f with the gaussian file you want to compare to and fix all the charges to the values obtained from chargefitconf.f.
Reads in several sets of alternative charges and compare them to potantials and moments in a gaussian file.
Originally made by Ulf Ryde.
Reads in a turbomole coord file and change the number of the internal coordinates according to a "change file" with the old and new numbers.
tilt.f and pilt.f
Calculates the tilt of the A-ring in a porphyrin, as the angle between the plane defined by the nitrogen and the two outer carbons of one pyrrole ring and the plane defined by the remaining three nitrogens. tilt.f uses a turbomole coord-file, and needs the atoms as an input. pilt.f uses a pdb file as the input and find the atoms from the atom names. pilt.f is made by Ulf Ryde.
Improvement of pilt.f to calculate the tilt of all four rings. Not completed.