Hello.
I am doing geometry optimization and Raman spectra calculations for organic crystals with CASTEP program. I am using PBE-D (D - Grimme correction) method.
We recently updated our Material Studio from 6.0 to 6.1 version and it turned out, that actually CASTEP cannot calulate PBE-D frequencies with default Linear Response Procedure. In CASTEP forum, Dr Keith Refson recommended to use finite displacement method. Unfortunately I don't see this option in Material Studio. Yes, I can specify "Finite displacement" for Phonons (attached picture), but I didn't find this option for "Polarizability, IR and Raman Spectra".
So, when I run CASTEP in Material Studio, Phonons calculations run OK, but in next step, when it starts to calculate Raman spectra the program exits with the following error:
% DFT-SEDC: DFT SemiEmpirical Dispersion interaction Correction module
% +----------------------------------------------------------------------+
%
% Copyright (c) 2008 Erik McNellis and Joerg Meyer, Fritz-Haber-Institut
% der MPG. Distributed under the GNU Lesser General Public License (LGPL).
% Please cite "Erik R. McNellis, Joerg Meyer, and Karsten Reuter,
% Phys. Rev. B 80, 205414 (2009)" in all publications using this module.
%
% 'G06'/PBE PBC image shells counted = 9
% 'G06'/PBE total energy correction = -11.28936958 [eV]
% 'G06'/PBE correction |F|max = 0.07414542 [eV/A]
???????????????????????????????????????????????????????????????????????????????
WARNING: Density Functional Perturbation Theory (linear response) with
semi-empirical dispersion correction is not implemented.
Calculation A B O R T E D
???????????????????????????????????????????????????????????????????????????????
If somebody knows how to specify finite displacement method for frequencies calculation using Material Studio?
So far I just manually inserted the following command in Efield.param file
calculate_raman : true
phonon_method : finitedisplacement
and run it manually (without Material Studio) in my cluster. But I hope there is a normal way to do it.
Thank you,
Boris