Print molden file each MD step

Questions
#1

Hello

Do you know a way to print molden files for each step during MD?

I am intereseted in the analysis of QTAIM properties in each step of a excited state MD

Best regards!

#2

It looks like MOLDEN_FORMAT=2, along with PRINT_ORBITALS=TRUE, will do the trick. (I implemented this long ago to print Molden at each step of a geometry opt and it seems to work for AIMD also.) I tried the following test job, which is sample job aimd_mo.in with one line added:

$comment
The following job run AIMD using B3LYP energies and gradients.
MO coefficients are printed at each time step when
aimd_print>=2 and print_orbitals>0
$end

$molecule
0 1
O
H 1 0.95
H 1 0.96 2 104.5
$end

$rem
jobtype           aimd
exchange          b3lyp
basis             6-31G*
time_step         15
aimd_steps        10 
aimd_init_veloc   zpe
aimd_init_veloc   thermal Boltzmann distribution  
aimd_temp         300     (in Kelvin)
aimd_print        2
print_orbitals    10 print ALL occupied and 10 virtuals
debug_random_seed true
molden_format  2 ! added this to get Molden file at each step
$end

I assume (?) that QTAIM can use the occupied MOs to get the density and perform the analysis? Because those are all you will get from the Molden file.

#3

Thank you for the response!

Although wfn/wfx files are used to QTAIM analysis, I have had problems with wfn files printed by q-chem. For this reason I am trying the molden format to construct the electron density and then analyze it.

But, do you have a similar implementation for printing wfn each MD/opt step?
I think it’s not bad to know it.

Regards!

#4

I have not used QTAIM and therefore haven’t used the .wfn file. I ran a test job with

WRITE_WFN     filename

in the $rem section, and I do get back filename.wfn, with data structures that look reasonable. If you’re not able to process that file with QTAIM then please send a bug report to Q-Chem.

At present, the structure of the code does not allow the .wfn file to be printed at every step (either for geometry optimization or AIMD), because it’s set up to write to a single user-specified file name. That’s fixable (in a future version of the code), but you would need to submit a feature request to Q-Chem.