There are several gazillions of papers dealing with electron-phonon coefficients in graphene. It shouldn't be difficult to find some data to compare with. As far as I know, option electron_phonon='simple' should work for a single phonon wave-vector.
P. On Oct 2, 2012, at 18:42 , Elie M wrote: > Dear all, > > I am trying to do el-ph calculations only at the Gamma point for > graphene (as I want to compare it to another system where the > calculations are only feasible at the Gamma point). However the > values I am getting for lambda for graphene AT THE GAMMA POINT are : > > degauss lambda > > 0.005 13.442600 > > 0.015 2.303600 > > 0.020 1.756000 > > 0.025 1.436000 > > 0.030 1.228800 > > 0.035 1.085800 > > 0.040 0.983000 > > 0.045 0.906400 > > 0.050 0.847800 > I am using a 90 x90 x1 grid (in scf) for graphene and the ph file > has only one point nq1=0 nq2=0, nq3=0 (the Gamma point). > > It is already known that lambda for graphene is ~0.02. > (1) Do the above results mean that one cannot calculate el-ph > coefficients unless on a grid of phonons and then are the > calculations -at the Gamma point ONLY- useless and unexact? > > (2) or does this mean that the results did not converge due to a > small k-mesh in the scf calculations (90x90x1) and I need to > increase it to say 400x400x1? > > Any suggestions of any kind would also be ahighly appreciated. > > Thanks for your help > > Elie M > University of Notts > NG7 2RD > UK > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://pwscf.org/mailman/listinfo/pw_forum --- Paolo Giannozzi, Dept of Chemistry&Physics&Environment, Univ. Udine, via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222
