## Firefly and PC GAMESS-related discussion club

Learn how to ask questions correctly

** Re: Problem with Hessian and TDDFT calculations.. **
Thomas Pijper

thomaspijper@hotmail.com

Dear Siddheshwar,> I ran HEssian calculations on my sample first. I

> got NO imaginary frequencies. But I could not find

> "Equilibrium geometry located" text anywhere.

This is because you specified RUNTYP=HESSIAN. This performs a Hessian calculation. The message "Equilibrium geometry located" appears only with a completed geometry optimization (RUNTYP=OPTIMIZE or SADPOINT). Your geometry does correspond to a minimum on the PES.

> I run TDDFT calcs. But in that I am getting this error now:

>

> * ... LESS THAN 3.000

>

> **** THERE ARE ATOMS LESS THAN 0.100 APART, QUITTING... ****

Most likely you made an error in the $DATA group of the TDDFT calculation input. It could for example be that you specified a point group other than C1, but specified coordinates corresponding to the C1 geometry, thus causing some atoms to be specified twice. If you would like me to take a closer look at the problem, feel free to post the input file for your TDDFT calculation.

Kind regards,

Thom

On Mon Mar 3 '14 11:21am, Siddheshwar Chopra wrote

--------------------------------------------------

>Dear Sir,

>I ran HEssian calculations on my sample first. I got NO imaginary frequencies. But I could not find "Equilibrium geometry located" text anywhere. Now thinking that it is a global minimum, I run TDDFT calcs. But in that I am getting this error now:

> * ... LESS THAN 3.000

> **** THERE ARE ATOMS LESS THAN 0.100 APART, QUITTING... ****

>What is wrong here? What should I do next to rectify this. If the sample was not in global minima, then how come there were no imaginary freqs?

>Regards,

Mon Mar 3 '14 5:51pm

This message read **474** times