Neil Drummond wrote:Thanks for sending the graph. I think I'll stick to plane waves and pseudopotentials...

Best wishes,

Neil.

Hello Neil

I want to make one very important comment for that fitting

E = (a+b.tau+c.tau^2)/(1+D.tau)

Where:

a is E at (tau->0)

b is slope at (tau->0)

c/

d is slope at (tau->inf)

I interpolated all my data with this equation and got better or comparable to other eqs (within the error) results, but when the number of points at small tau is insufficient to determine the

b value because error of

b is compatible with its abs value, we can effectively set

b=0 and then reinterpolate the data with simple equation. In this case we can nevertheless determine

a with a small enough error and find out a parabolic-like dependence between E and tau at small tau.

This also explains many of the previously published E(tau) dependencies.

Best Vladimir.