[Pw_forum] about the feasibility of second order coefficient of Nonlinear Optical within PWSCF

[xu yuehua]

thank you.it seems somewhat complex.hehe

2008/2/19, Paolo Giannozzi <giannozz at nest.sns.it>:
>
>
> On Feb 18, 2008, at 14:08 , xu yuehua wrote:
>
> > i am writing to enquire that is there a way to get the second order
> > coefficient of Nonlinear Optical within PWSCF, directly or indirectly.
>
> second-order nonlinear optical coefficients, i.e. \gamma in the
> following formula, where P is the induced polarization and E the
> electric field: P=\alpha E + \beta E^2 + \gamma E^3 ? this is
> the fourth-order derivative of the energy wrt electric field and
> can be calculated using the second-order response to an
> applied electric field. The latter is calculated by the phonon
> code for the Raman calculation. The code already calculates
> the nonlinear optical coefficient \beta (called "electro-optical
> coefficients": I do not think this is correct, by the way). Static
> calculations, though (\omega=0), and no ultrasoft PP. So all
> ingredients are there, but require some programming. It is
> something that I wanted to do (and still want to do: it is useful
> to estimate how nonlinear optical properties change in phtalocyanines
> when deposited on some surfaces and doped), but it requires an
> amount of patience that I am afraid I no longer have. Anybody
> interested?
>
> Paolo
> ---
> Paolo Giannozzi, Dept of Physics, University of Udine
> via delle Scienze 208, 33100 Udine, Italy
> Phone +39-0432-558216, fax +39-0432-558222
>
>
>
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-- 
Xu Yuehua
physics Department of Nanjing university
China
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