Excited state opt energy & Isotope UV-Vis spectra

Questions
#1

Hi everyone!

I just started using Q-Chem (6.0.0) and I’m doing some test calculations optimizing the S0 and S1 states of CS2 using CCSD and EOM-CCSD. I have some (silly) questions about energies and UV-Vis spectra.

  1. I run the opt + freq calculations in the same input file. I know where to get the ZPE after a freq calculation, but for the electronic energy, should I use the final energy after the opt calculation,
 Found a minimum
                ---------------------------------
                       End of Verification
                ---------------------------------
 Final energy is -833.350866990839
        ******************************
        **  OPTIMIZATION CONVERGED  **
        ******************************

or something else?

My $rem section for the excited state calculation is

$rem
JOBTYP opt
METHOD eom-ccsd
BASIS gen
PURECART 11
EE_STATES 3
CC_STATE_TO_OPT [1,2]
N_FROZEN_CORE FC
SYM_IGNORE true

I’m pretty certain that this is correct and optimizes the S1 state, but it would be nice if someone more experienced could confirm this.

@@@

  1. I was reading the manual and noticed that Q-Chem has the ability to calculate vibrationally resolved UV-Vis spectra, which is really cool! Can I also get spectra for species with different isotopes? I know that adding ISOTOPES 1 and the $isotopes section calculates the vibrations, but is there a way to do that for the UV-Vis spectrum?

Any help/comments are appreciated!
Cheers,

Robert

#2

Regarding the first question, you should be able to confirm by looking at the HF or CCSD ground-state energy and comparing that to the final energy.

Regarding isotopes in UV/Vis, you will have to try it. May not have been enabled.