[Pw_forum] a question about parameters for ecutwfc and ecutrho

[Paolo Giannozzi]

On Monday 17 October 2005 10:10, Chaohao Hu wrote:

> I am confused to the difference between ecutwfc and ecutrho.
> In general plane wave code, 

using norm-conserving pseudopotentials,

> only the energy cutoff for wavefunctions  is adequate.
> Why do we need ecutrho parameter in PWSCF?

because it may be useful with ultrasoft pseudopotentials.
See for instance Phys. Rev. B 47, 10142 (1993);
J. Chem. Phys. 120, 5903-5915 (2004). The latter is available
here: http://web1.sns.it/~giannozz/Papers/JCP_57.pdf

Paolo
-- 
Paolo Giannozzi             e-mail:  giannozz at nest.sns.it
Scuola Normale Superiore    Phone:   +39/050-509876, Fax:-563513 
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