I recently got interested in printing orbitals and densities as cube files by using the new version of the $plots section, which is invoked with MAKE_CUBE_FILES = TRUE and PLOTS = TRUE.
Given the following input:
O -2.1904701 0.5202006 0.0237374
H -1.2011437 0.4799213 0.0090967
H -2.4798356 -0.3698583 -0.2997841
BASIS = 6-31G*
MAKE_CUBE_FILES = TRUE
PLOTS = TRUE
!STATE_ANALYSIS = TRUE
METHOD = PBE
CIS_N_ROOTS = 2
CIS_TRIPLETS = 0
CIS_SINGLETS = 1
NTO_PAIRS = 4
grid_range (-8,8) (-8,8) (-8,8)
grid_points 150 150 150
There are 3 issues I would like to discuss when running it with Q-Chem:
- A minor thing, I think there is a typo in the Q-Chem manual since the “natural_transition_orbitals” keyword in the “$plot” section is not recognized while “natural_transition_orbital” is.
- If I run the input with STATE_ANALYSIS = TRUE (commented in the example above) the job crashes with an error involving the FM_READ function. Is this keyword incompatible with printing cube files as described before?
- If NTOs are successfully printed. How do I understand which pair corresponds to the highest singular value? Files are named: NTO.TDA.state1.2.cube, NTO.TDA.state1.3.cube, … , up to NTO.TDA.state1.9.cube but this doesn’t help with the ordering criteria.