## Firefly and PC GAMESS-related discussion club

Learn how to ask questions correctly

Re: Transition dipole moments

Alex Granovsky
gran@classic.chem.msu.su

Dear Siarhei,

On Mon Feb 16 '15 7:40pm, Siarhei wrote
---------------------------------------

>Could you please tell, in TDDFT calculation
>dipole moments of the excited states μ_11,
>μ_22 and so on (unrelaxed dipole moments) in the table
>with the transition dipole moments , are written with
>the reference to the ground state, or these are absolute values?

These are absolute values in atomic units.

>And another question, related to this topic.
>In this thread in discussion on relaxed/unrelaxed density excited state properties
>http://classic.chem.msu.su/cgi-bin/ceilidh.exe/gran/gamess/forum/?C34df668afbHW-7216-1405+00.htm
>you mentioned, that it is possible to "calculate dipole moment as the derivative of energy wrt. to
>electric field using runtyp=ffield. This quantity can be directly
>compared with dipole moment calculated using relaxed density."
>As I run the calculation, using
>runtyp=ffield and specified
>\$FFCALC IAXIS=3 JAXIS=1 \$END

>I can find only unrelaxed density dipole moment, but there is no relaxed density dipole moment.
>Maybe I'm missing something very obvious, but I have no idea what could I miss.

To get dipole, you need to use

``` \$FFCALC IAXIS=3 JAXIS=0 \$END for Z component,
or
\$FFCALC IAXIS=2 JAXIS=0 \$END for Y component,
or
\$FFCALC IAXIS=1 JAXIS=0 \$END for X component,
```

To compare numerically computed response type dipole
with analytically computed one, add

``` \$dft tdprp=.t.
```

Hope this helps.

Kind regards,
Alex Granovsky

Wed Feb 18 '15 1:25am
This message read 986 times