high local exchange functional reg.

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Mausumi
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high local exchange functional reg.

#1 Post by Mausumi » Tue Apr 30, 2024 12:12 pm

Dear All,
I need to calculate the band structure of my system using a high local exchange functional. I have come across a paper titled 'HLE17: An Improved Local Exchange−Correlation Functional for Computing Semiconductor Band Gaps and Molecular Excitation Energies.' In this paper, they use VASP software for band structure calculations. However, when attempting to perform the calculations in VASP, an error occurs: 'Error: This functional is not implemented. I REFUSE TO CONTINUE WITH THIS SICK JOB... BYE!!!'

Attached is my INCAR file with the following parameters:
Global Parameters
ISTART = 1 (Read existing wavefunction; if there)
LREAL = Auto (Projection operators: automatic)
ENCUT = 540
NELM = 1000
EDIFF = 1E-5
PREC = Normal
ALGO = A
ISPIN =2
LORBIT = 11
LWAVE = .TRUE. (Write WAVECAR or not)
LCHARG = .TRUE. (Write CHGCAR or not)
SIGMA = 0.05
METAGGA=HLE17
LASPH=.TRUE.
LMAXMIX=4

Please help me solve this issue.

Thanks and regards,
Mausumi

fabien_tran1
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Re: high local exchange functional reg.

#2 Post by fabien_tran1 » Tue Apr 30, 2024 12:29 pm

Hi,

HLE17 is not implemented directly in VASP (it is not listed at https://www.vasp.at/wiki/index.php/METAGGA), but can be used via Libxc, which is an external library of exchange-correlation functionals. If your VASP installation was compiled with Libxc, then HLE17 can be specified with the following two lines:
METAGGA=LIBXC
LIBXC1=MGGA_XC_HLE17

More information about Libxc can be found here:
https://www.vasp.at/wiki/index.php/METAGGA
https://www.vasp.at/wiki/index.php/LIBXC1

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