4.3 Basic SCF Job Control

4.3.2 Examples

(June 30, 2021)

Provided below are examples of Q-Chem input files to run ground state, HF single point energy calculations.

Example 4.2  Example Q-Chem input for a single point energy calculation on water. Note that the declaration of the single point $rem variable is redundant because it is the same as the Q-Chem default.

$molecule
   0  1
   O
   H1  O  oh
   H2  O  oh  H1  hoh

   oh  =   1.2
   hoh = 120.0
$end

$rem
   JOBTYPE       sp       Single Point energy
   METHOD        hf       Hartree-Fock
   BASIS         sto-3g   Basis set
$end

View output

Example 4.3  UHF/6-311G calculation on the Li atom. Note that correlation and the job type were not indicated because Q-Chem defaults automatically to no correlation and single point energies. Note also that, since the number of α and β electron differ, MOs default to an unrestricted formalism.

$molecule
   0,2
   Li
$end

$rem
   METHOD     HF       Hartree-Fock
   BASIS      6-311G   Basis set
$end

View output

Example 4.4  ROHF/6-311G calculation on the Lithium atom.

$molecule
   0,2
   3
$end

$rem
   METHOD         hf       Hartree-Fock
   UNRESTRICTED   false    Restricted MOs
   BASIS          6-311G   Basis set
$end

View output