Quantum Chemistry

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Note the three levels:

• L1: level for exploration
• L2 = high-level: level for good geometries and frequencies
• L3 = single-point : level for accurate electronic energies

Pro tip: If you want to add additional keywords to your calculations, you can type them as part of the basis set. E.g., adding dispersion correction at the L2 level looks like "high_level_basis": "6-311++G** EmpiricalDispersion=GD2" in the json input file.

parameter	default	description	use with...
qc	"gauss"	The quantum chemistry package to use: available ones are 'gauss' for Gaussian, "nwchem" for NWChem and "qchem" for Q-Chem, but currently only Gaussian is supported.
methodclass	"dft"	Class of methods used, other available values are "mp2" or "scf".	NWChem
qc_command	"g16"	Command to run the quantum chemistry code.	all
method	"b3lyp"	Low-level (L1) method for reaction and conformational searches.	all
basis	"6-31G"	Low-level (L1) basis set for reaction and conformational searches.	all
barrierless_saddle_method	"b3lyp"	Low-level (L1) method for the barrierless_saddle family reaction and conformational searches.	all
barrierless_saddle_basis	"6-31G"	Low-level (L1) basis set for the barrierless_saddle family reaction and conformational searches.	all
calcall_ts	1	1: Use CalcAll in the final optimization of saddle points at the L1 level. It is quite crucial in certain cases to use this setting. 0: do not
high_level_method	"M062X"	High-level (L2) method for energy and frequency calculations.	all
high_level_basis	"6-311++G(d,p)"	High-level (L2) basis set for energy and frequency calculations.	all
barrierless_saddle_method_high	"b3lyp"	High-level (L2) basis set for energy and frequency calculations for the barrierless_saddle family.	all
barrierless_saddle_basis_high	"6-31G"	High-level (L2) basis set for energy and frequency calculations for the barrierless_saddle family.	all
integral	''	Integral grid, only used for the high-level (L2) calculations.	Gaussian
opt	''	Convergence threshold in L2 calculations, as in Opt=VeryTight.	Gaussian
irc_maxsteps	30	Maximum number of steps in IRC calculations.	all
irc_stepsize	20	Step size in IRC calculations in units of 0.01 Bohr.	all
L3_calc	0	Turn on or off the generation of L3 input files and the reading of the L3 output files.
single_point_qc	molpro	Code to use for single-point (L3) energies.
single_point_template	''	If not specified, the default template is used. The user can specify a path to a modified file. An example is shown below this table.	'all'
barrierless_saddle_single_point_template	''	Molpro template for the barrierless_saddle family's L3 calculation. The user needs to provide this template, typically a CASPT2 calculation.	'all'
barrierless_saddle_norbital	0	Number of active orbitals for the L3 barrierless_saddle calculation.
barrierless_saddle_nelectron	0	Number of electrons in the active orbitals for the L3 barrierless_saddle calculation.
barrierless_saddle_nstate	0	Number of states for the L3 barrierless_saddle calculation.
single_point_command	''	Command line string to run Molpro. User should always define this parameter if running single point calculations. If -n option for Molpro is used, the value (i.e. -n 4) should match the single_point_ppn value defined below.	Molpro
single_point_key	''	String to parse when searching for the energy in output. User should always define.	Molpro
barrierless_saddle_single_point_key	''	String to parse when searching for the energy in output for the L3 barrierless_saddle calculation. User should always define.	Molpro

While KinBot is fully restartable, some parameters cannot be changed upon restart without compromising the calculations. These are marked with an asterisk (*).

KinBot's internal Molpro template:

***,{name}
memory,1600,M
geomtyp=xyz
geometry={{
{natom}
{name}
{geom}
}}
{{uhf;wf,{nelectron},1,{spin},{charge}}}

basis=cc-pvdz-f12
rhf
CCSD(T)-F12

myena(1) = energy(1)
myenb(1) = energy(2)

basis=cc-pvtz-f12
rhf
CCSD(T)-F12

myenergy(2) = energy(1)
myenb(2) = energy(2)
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