Positron enhacement includes correction for semiconductors?

dr_sferrari · Post by **dr_sferrari** » Thu May 05, 2011 5:15 pm

Hi all,
I am working in calculating positron lifetimes. I have a question about enhacement factors: does any of the options of ixcpositron includes the correction for screening of positron in semiconductors given by (1-1/ε_infinite) r_s^3 ; where ε_infinite is the high-frequency dielectric constant of the semiconductor?

Second question: ixcpositron give the annihilation rate enhancement factor,
Selecting ixcpositron=1 uses " Boronski and Nieminen full modelisation and RPA limit"
while fulll modelsation seems to be the formula (given in the appendix of the article Boronski and R.M. Nieminen, Phys. Rev. B 34, 3820 (1986).) :
gBN = 1 + 1.23 r_s + 0.8295*r_s^(3/2) - 1.26 r_s^2 + 0.3286r_s^(5/2)+ (1/6)*r_s^3

What is the formula for the "RPA limit"????????