MOKIT Documentation

3.1 Quick Start with Examples

3.1.1 Automatic multiconfigurational computations

The input syntax of the automr program is the same to Gaussian gjf. For example, the input file 00-h2o_cc-pVDZ_1.5.gjf of the water molecule at d(O-H) = 1.5 A is shown below

%mem=4GB
%nprocshared=4
#p CASSCF/cc-pVDZ

mokit{}

0 1
O      -0.23497692    0.90193619   -0.068688
H       1.26502308    0.90193619   -0.068688
H      -0.73568721    2.31589843   -0.068688

Run the following command

automr 00-h2o_cc-pVDZ_1.5.gjf >00-h2o_cc-pVDZ_1.5.out 2>&1

The automr program will successively perform HF, GVB, and CASSCF computations by calling Gaussian, GAMESS and PySCF, respectively. The active space will be automatically determined as (4,4) during computations. Detailed instructions for automr input can be found in Section 4.1 - 4.4.

See more examples in Section 5.1.

3.1.2 Automatic multireference computations

The automr program supports automatic computation of many multireference methods, e.g. NEVPT2/CASPT2/MRCISD/MC-PDFT.

%mem=8GB
%nprocshared=4
#p NEVPT2/cc-pVTZ

mokit{}

0 1
O      -0.23497692    0.90193619   -0.068688
H       1.26502308    0.90193619   -0.068688
H      -0.73568721    2.31589843   -0.068688

3.1.3 Automatic single-reference computations

There are many factors to be considered in some advanced single-reference computations: the auxiliary basis set for RIJK, the auxiliary basis set for correlated methods, the complementary auxiliary basis sets for F12 calculations, SCF convergence, HF wave function stability, etc. These factors can be automatically dealt with by using autosr. For example,

%mem=8GB
%nprocshared=4
#p CCSD(T)-F12/cc-pVTZ-F12

mokit{CC_prog=ORCA}

0 1
O         0.00000000     0.00000000     0.06200700
H         0.00000000    -0.78397600    -0.49205200
H         0.00000000     0.78397600    -0.49205200

Run the following command to submit the autosr job.

autosr h2o.gjf >h2o.out 2>&1 &

autosr will call Gaussian to perform HF/cc-pVTZ-F12 calculations, transfer MOs to ORCA, and call ORCA to perform the CCSD(T)-F12/cc-pVTZ-F12 calculation. cc-pVTZ-F12 is not a built-in basis set in Gaussian, but autosr will deal with this problem automatically since MOKIT has included this basis set.

3.1.4 Using one utility

Running the following command

fch2inp h2o.fch

will generate the GAMESS input file h2o.inp, in which the Cartesian coordinates, basis set data, molecular orbitals(MOs) and some necessary keywords are written. If the MOs in h2o.fch are RHF/ROHF/UHF MOs, you can simply submit the GAMESS job and you will find the SCF is converged in ~1 cycle in GAMESS. If you want to perform other types of calculation, remember to modify h2o.inp. Note that keywords nosymm int=nobasistransform should be written in h2o.gjf before submitting the Gaussian job, since this facilitates the orbital transferring and SCF convergence.

Some commonly used utilities and their functionalities are listed below

You can search a utility and read the documentations in Section 4.5 or 4.6.