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3.3 KiB
3.3 KiB
Hartree-Fock
#+PROPERTY
In this example, we write a program that makes a Hartree-Fock
caculation. The molecule is read in xyz
format and a Gaussian
atomic basis set in GAMESS format.
Header
module Command_line = Qcaml.Common.Command_line
module Util = Qcaml.Common.Util
let () =
Command-line arguments
We use the Command_line
module to define the following possible
arguments:
-b --basis
: The name of the file containing the basis set-x --xyz
: The name of the file containing the atomic coordinates-c --charge
: The charge of the molecule-m --multiplicity
: The spin multiplicity
Definition
let open Command_line in
begin
set_header_doc (Sys.argv.(0) ^ " - QuAcK command");
set_description_doc "Computes the one- and two-electron hartree_fock on the Gaussian atomic basis set.";
set_specs
[ { short='b' ; long="basis" ; opt=Mandatory;
arg=With_arg "<string>";
doc="Name of the file containing the basis set"; } ;
{ short='x' ; long="xyz" ; opt=Mandatory;
arg=With_arg "<string>";
doc="Name of the file containing the nuclear coordinates in xyz format"; } ;
{ short='m' ; long="multiplicity" ; opt=Optional;
arg=With_arg "<int>";
doc="Spin multiplicity (2S+1). Default is singlet"; } ;
{ short='c' ; long="charge" ; opt=Optional;
arg=With_arg "<int>";
doc="Total charge of the molecule. Specify negative charges with 'm' instead of the minus sign, for example m1 instead of -1. Default is 0"; } ;
]
end;
Interpretation
let basis_file = Util.of_some @@ Command_line.get "basis" in
let nuclei_file = Util.of_some @@ Command_line.get "xyz" in
let charge =
match Command_line.get "charge" with
| Some x -> ( if x.[0] = 'm' then
~- (int_of_string (String.sub x 1 (String.length x - 1)))
else
int_of_string x )
| None -> 0
in
let multiplicity =
match Command_line.get "multiplicity" with
| Some x -> int_of_string x
| None -> 1
in
Computation
We first read the xyz
file to create a molecule:
let nuclei =
Qcaml.Particles.Nuclei.of_xyz_file nuclei_file
in
Then we create an Gaussian AO basis using the atomic coordinates:
let ao_basis =
Qcaml.Ao.Basis.of_nuclei_and_basis_filename ~nuclei basis_file
in
We create a simulation from the nuclei and the basis set:
let simulation = Qcaml.Simulation.make ~nuclei ao_basis in
and we can make the Hartree-Fock computation:
let hf = Qcaml.Mo.Hartree_fock.make ~guess:`Huckel simulation in
Output
We print the convergence of the calculation:
Format.printf "@[%a@]" (Mo.Hartree_fock.pp) hf