[Pw_forum] Raman

[Paolo Giannozzi]

On Wed, Dec 9, 2015 at 1:30 PM, Ilya Ryabinkin <igryabinkin at gmail.com>
wrote:

> In a nutshell: you have been told: "third-order derivatives are not
> implemented".


not exactly that. What is not implemented is "the third-order functional
derivative of the exchange-correlation energy with respect to the charge
density", which is an ingredient needed for computation of third-order
energy derivatives. It is implemented for LDA only. Of course one can
always comment out the check and keep the LDA part only. This will not
however solve the problem, because in the scf calculation:

 >    Si   28.08600  Si.tpss-mt.UPF
>     O   15.99940  O.tpss-mt.UPF

TPSS meta-GGA is used, and phonons for meta-GGA are not implemented.

Paolo

-- 
Paolo Giannozzi, Dept. Chemistry&Physics&Environment,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222
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