HFALPHA: Difference between revisions

Revision as of 10:50, 28 April 2021

Default: HFALPHA

= 6/sqrt(ENMAX)/(2π)

if HFRCUT is 0

Description: HFALPHA sets the decay constant used in the method of Massida, Posternak, and Baldereschi, which is activated by HFRCUT=0.

HFALPHA sets the decay constant in the error-function-like charge distribution for the method of Massida, Posternak, and Baldereschi^[1]. The error-function-like charge distribution is used to calculate the difference between the isolated probe charge and the periodically repeated probe charge in a homogenous background. The default for HFALPHA is 6/sqrt(ENMAX)/(2π) in atomic units. This usually yields robust and accurate results in the range of meV compared to the Ewald summation used for a regular k-mesh. For more details, see HFRCUT=0.

Related Tags and Sections

HFRCUT

↑ S. Massidda, M. Posternak, and A. Baldereschi, Phys. Rev. B 48, 5058 (1993).

[massidda:prb:93-1] S. Massidda, M. Posternak, and A. Baldereschi, Phys. Rev. B 48, 5058 (1993).

[1]

@@ Line 1: / Line 1: @@
-{{TAGDEF|HFALPHA|[real]|-1}}
+{{TAGDEF|HFALPHA|[real]}}
+{{DEF|HFALPHA|6/sqrt({{TAG|ENMAX}})/(2π)|if {{TAG|HFRCUT}} is 0}}
-Description: {{TAG|HFALPHA}} specifies how the Coulomb kernel is approximated at G=0 when the Fock energy and the exchange potential are evaluated.
+Description: {{TAG|HFALPHA}} sets the decay constant used in the method of Massida, Posternak, and Baldereschi, which is activated by {{TAG|HFRCUT}}=0.
 ----
-For details we refer to {{TAG|HFRCUT}}.  If the method of Massida, Posternak and Baldereschi is used [S. Massida, M. Posternak, and A. Baldereschi, Phys. Rev. B 48, 5058 (1993)], {{TAG|HFALPHA}} specifies the
-decay constant in the error-function-like charge distribution that is used to calculate the difference between the isolated probe charge and the periodically repeated probe charge in the homogenous background. The default for {{TAG|HFALPHA}}
+{{TAG|HFALPHA}} sets the decay constant in the error-function-like charge distribution for the method of Massida, Posternak, and Baldereschi{{cite|massidda:prb:93}}. The error-function-like charge distribution is used to calculate the difference between the isolated probe charge and the periodically repeated probe charge in a homogenous background. The default for {{TAG|HFALPHA}} is 6/sqrt({{TAG|ENMAX}})/(2π) in atomic units. This usually yields robust and accurate results in the range of meV compared to the Ewald summation used for a regular k-mesh. For more details, see {{TAG|HFRCUT}}=0.
-is 6/sqrt({{TAG|ENMAX}})/(2 pi) (in atomic units).
 == Related Tags and Sections ==