Groundstate geometry of isolated molecule for response funct [SOLVED]

[Seba Darshan]

Dear Abinit users

I have been trying to obtain the ground state geometry of an isolated molecule. I modified the k-point grid definition in "trf1_1.in" for AlAs to the desired molecule as follows:
kptopt 0
nkpt 1

and used the ground state configuration obtained from that calculation for response function calculation of full dynamical matrix at the Gamma point. I used the following input variables for defining the k point grid.
kptopt 2
ngkpt 1 1 1
nshiftk 1
shiftk 0.0 0.0 0.0

My doubt is that whether I need to use the same k-point grid definition for the above two calculations or for all response function calculations.

Any help in this regard is greatly appreciated

Thanks in advance
Seba

[mverstra]

Hi Seba,

for an isolated system there is never any need for k-points.

[Seba Darshan]

Hi Seba,

for an isolated system there is never any need for k-points.

Hai mverstra,

Thank you for the reply. But for my previous post on "How to calculate the phonon frequencies of an isolated molecule", you have replied to go ahead with k point definition as follows in the "trf1_4.in" for the isolated molecule:

kptopt 2
ngkpt 1 1 1
nshiftk 1
shiftk 0.0 0.0 0.0

So I am confused now on the k point definition in the input file.

Kindly guide me in this regard.

Thanks in advance
Seba

[mverstra]

Yes - what I mean is: 1 kpt Gamma only is enough.