Dear espresso users, 1) I'm a bit confused with the implementation of the Makov-Payne electrostatic corrections in PW/makov-payne.f90 in Version 4.2: - In their original paper, Makov and Payne define the first order correction E11 = - \alpha * q^2/(2\epsilon* L). This quantity should be negative for cubic systems, however the writing statement in PW/makov-payne.f90 subroutine defines the correction to be -E11 (leading to a positive value). - The second order correction E12 is propertional to q Q/L^3 and is also defined as -E12 in the PW/makov-payne.f90 subroutine. - The total energy should be Etot = E0 + E11 + E12 = E0 - \alpha * q^2/(2\epsilon* L) + 2 \pi * q * Q / ( 3 \epsilon L^3), however it is implemented as E0-E11-E12.
2) Why the DCC correction is disabled in version 4.2? Indeed when setting asume_isolated = 'dcc' and &EE input parameters to their default values, I obtain an error message "DCC correction is disabled". Looking in the PW/input.f90 subroutine, one found that the dcc correction is disabled by an immediate call to errore subroutine. Please can any one verify if I'm correct or did I miss something. Best regards -- Dr. Ilyes Hamdi, Assistant professor Department of Electronic and Automatics, Institute of Applied Sciences and Technology Gafsa, Tunisia -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20110405/18a46f1b/attachment.htm
