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** 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.

to your input.

Hope this helps.

Kind regards,

Alex Granovsky

Wed Feb 18 '15 1:25am

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