[QE-users] Custom xc functionals

[A.M. Shipley]

Dear all,

Is there some way to use "custom" exchange-correlation functionals in 
QE? For example, in CASTEP, as well as using the standard functionals, 
you are able to define something such as

%block xc_definition
LDA-X   0.20127148358147
B88_X   0.79872851641853
LYP_C   0.61544187700225
LDA-C   0.38455812297775
%endblock xc_definition

where you mix together fractions of different standard functionals. I 
ask this because I have some custom exchange-correlation functionals 
that have been carefully fitted to work in a certain situation (in fact 
one of them is defined by the ratios given above).

I know developers on other codes have somewhat hidden features like this 
away in order to discourage users from just fiddling with ratios until 
they get the answers they want/expect with no real meaning behind them, 
so I thought I'd check here if such a feature exists.

Best wishes,
Alice

Department of Physics
University of Cambridge