Phonon calculation about q wavevectors setting

Gang Tang · Post by **Gang Tang** » Wed Jan 13, 2021 8:21 pm

At present, I am a little confused about the setting of the q vector in the phonon calculation process.

According to the abinit official website tutorial (https://docs.abinit.org/tutorial/rf2/) and workshop resources (http://palata.fzu.cz/abinitschool/downl ... honons.pdf), there are two different q vector setting methods. For examples:

Method 1: from https://docs.abinit.org/tutorial/rf2/

Code: Select all

#Q vectors for all datasets

#Complete set of symmetry-inequivalent qpt chosen to be commensurate
# with kpt mesh so that only one set of GS wave functions is needed.
#Generated automatically by running GS calculation with kptopt=1,
# nshift=0, shiftk=0 0 0 (to include gamma) and taking output kpt set
# file as qpt set. Set nstep=1 so only one iteration runs.

     nqpt   1            # One qpt for each dataset (only 0 or 1 allowed)
                         # This is the default for all datasets and must
                         #  be explicitly turned off for dataset 1.

     qpt2   0.00000000E+00  0.00000000E+00  0.00000000E+00
     qpt3   0.00000000E+00  0.00000000E+00  0.00000000E+00
     qpt4   2.50000000E-01  0.00000000E+00  0.00000000E+00
     qpt5   5.00000000E-01  0.00000000E+00  0.00000000E+00
     qpt6   2.50000000E-01  2.50000000E-01  0.00000000E+00
     qpt7   5.00000000E-01  2.50000000E-01  0.00000000E+00
     qpt8  -2.50000000E-01  2.50000000E-01  0.00000000E+00
     qpt9   5.00000000E-01  5.00000000E-01  0.00000000E+00
     qpt10 -2.50000000E-01  5.00000000E-01  2.50000000E-01

Method 2: from http://palata.fzu.cz/abinitschool/downl ... honons.pdf

Code: Select all

    nqpt  1
    iqpt: 0
    iqpt+ 1

Compared to Method 1, Method 2 is more convenient. Because method 1 needs to manually set the q vector.
I want to know if Method 2 is currently available in version Abinit 9.2.2 version and how to determine the value of ndtset.

See the attachment for the complete input file of the two methods.

Thanks very much.