Usage:
resp [-O] -i input -o output -p punch -q qin -t qout
-e espot -w qwts -s esout
RESP (Restrained ElectroStatic Potential) fits the quantum mechanically calculated electrostatic potential (esp) at molecular surfaces using an atom-centered point charge model. This method was developed by Christopher Bayly.
A quantum mechanical program, such as Gaussian (g94) or GAMESS, must be used to generate the ESP input for RESP. See src/resp/0README for tips for interfacing such programs with RESP. See Appendix D for background on charge fitting.
file flag fortran purpose
name unit
input -i 5 required input options
output -o 6 a/p output of results
punch -p 7 a/p synopsis of results
qin -q 3 optional replacement charges
qout -t 19 a/p ouput of current charges
espot -e 10 required input of ESP's and coordinates
qwts -w 4 optional input of new weight factors
esout -s 20 optional generated esp values for new
charges
a/p = always produced
Input included in the "-i" file
-1st line-
TITLE
input: a character string
-2nd section-
Begin with namelist " &cntrl"
(see example at end)
inopt = 0 normal run
= 1 cycle through a list of different qwt
read from -w unit
ioutopt = 0 normal run
= 1 write restart info of new esp etc to
unit -es (esout unit)
iqopt = 1 reset all initial charges to zero (default)
= 2 read in new initial charges from -q (qwt)
(normally not used:
= 3 read in new initial charges from -q (qwt)
and perform averaging of those new
initial charges according to ivary values
)
nmol = n the number of molecules in a multiple molecule
fit (default 1)
ihfree = 0 all atoms are restrained
= 1 hydrogens not restrained (default)
irstrnt = 0 harmonic restraints (old style)
= 1 hyperbolic restraint to charge of zero (default)
= 2 only analysis of input charges; no
charge fitting is carried out
iunits = 0 atom coordinates in angstroms (default)
= 1 " " " bohrs
qwt = normally use 0.0005 for Stage 1 (default)
" " 0.001 for Stage 2
end namelist " &cntrl" with " &end"
-3rd "line"-
wtmol .... relative weight for the molecule if
multiple molecule fit (1.0 otherwise)
input: real number
-4th "line"-
subtitle for molecule
input: a character string
-5th "line"-
charge, iuniq ( the number of atoms)
input: 2I5
-6th "area"-
one line for each atom
input: 2I5
Atomic number, ivary
ivary
= 0 charge varied independently of previous
centers
= n current charge fitted together with
center "n"
= -99 charge frozen at "initial charge" value
typically read in unit "qin"
-7th- "area"
charge constraints... blank line if no constraints
input: I5,F10.5
ngrp = number of centers in the group associated with this
constraint (i.e. the number of centers to be read in)
grpchg(i) = charge to which the associated group of atoms
(given on the next card) is to be constrained
-7.1th-
imol, iatom
format(16I5)
the list (ngrp long) of the atom indices of those atoms to be
constrained to the charge specified on the previous line.
*blank to end
-8th "area"-
intermolecular charge constraints
same format as indvidual molecule constraints
*blank to end
-9th "area"-
Multiple molecule atom equivalencing
format is analagous to 7th area and 7.1
ngrp(I5) and then, on separate lines: imol,iatoms(16I5)
*blank to end
Other file formats
-q input of replacement charges if requested
(note: same format as produced by -q)
input: 8f10.6
-w input of new weight factors if requested
input: i5 nqwt number of new weights to cycle thru
input: f10.5 new weights
nqwt lines
-e input of ESP's and coordinates
-1st line-
n_atoms n_esp_points
input: 2i5
-2nd- 2->natoms+1 lines-
atom coordinates
x,y,z (in Bohrs)
input 17x,3e16.7
-3rd natoms+2->natoms+2+nesp lines-
potential and coordinate
qpot,x,y,z (in a.u.,bohrs)
input 1X,4E16.7
Several examples of input and output files are in
$AMBERHOME/examples/resp_charge_fit; these should be consulted by those
interested in running the program.