[Pw_forum] Are the units of the "efield" tag in the PW.x and CP.x codes different?

[Paolo Giannozzi]

S. Sanchez wrote:

> What I do not understand is the fact that the label "efiled" in the 
> INPUT_PW.html webpage reports the following information:
> Amplitude of the finite electric field (in Ry a.u.; 1 a.u. = 
> 36.3609*10^10 V/m)
> 
> If I follow the above expression, i.e., (51.4221*10^10 
> V/m)/SQRT(2)=36.3609*10^10 V/m, the units of the "finite electric field" 
> should be Hartrees and not in Rydbergs, right?

"eamp" is in "Hartree" atomic units, i.e. 51.4221*10^10 V/m
"efield" is in "Rydberg" atomic units, i.e. 36.3609*10^10 V/m,
i.e. 51.4221*10^10 V/m/sqrt(2) (where sqrt(2)=e, in Ry a.u.)

> Also, in the INPUT_CP.html webpage, the same label "efield" reports the 
> following:
> Amplitude of the finite electric field (in a.u.; 1 a.u. = 36.3609*10^10 V/m)

this is actually incorrect (I think): in CP the electric field is
in "Hartree" atomic units = 51.4221*10^10 V/m

P.
-- 
Paolo Giannozzi, Democritos and University of Udine, Italy