--- On Wed, 19/1/11, suman kalyan sahoo <[email protected]> wrote:
From: suman kalyan sahoo <[email protected]> Subject: mismatch in band structure of bulk tin in beta and alpha phase. To: [email protected] Date: Wednesday, 19 January, 2011, 12:17 AM Dear users I am doing calculation on bulk beta-Sn (tin),as well as alpha tin. I am taking the the pseudo potential given in siesta home website first few lines are Sn pb nrl nc ATM 3.2.2 9-APR-07 Troullier-Martins 5s 2.00 r= 2.43/5p 2.00 r= 2.49/5d 0.00 r= 2.82/4f 0.00 r= 2.82/ 4 0 1176 4.957504353333E-05 1.250000000000E-02 4.000000000000 Radial grid follows 6.235772827088E-07 1.254998202050E-06 1.894361418827E-06 2.541766834843E-06 3.197315608511E-06 3.861110170662E-06 4.533254240545E-06 5.213852842040E-06 5.903012320063E-06 6.600840357183E-06 7.307445990452E-06 8.022939628438E-06 and basis set for Sn as follows %block PAO.Basis Sn 2 n= 5 0 2 6.030 4.773 n= 5 1 2 P 1 7.675 5.615 %endblock PAO.Basis as well as %block PAO.Basis # Define Basis set Sn 3 # Species label, number of l-shells n=5 0 2 P 1 # n, l, Nzeta, Polarization, NzetaPol 5.830 4.597 1.000 1.000 n=5 1 2 # n, l, Nzeta 7.675 5.545 1.000 1.000 n=4 2 1 # n, l, Nzeta 3.449 1.000 %endblock PAO.Basis With this potential and both basis set the parameters (Lattice constant,cohesive energy and band structure)for tin in diamond form is well reproduce with the previous literature. But when i draw the band structure for bct ( beta Sn) phase , the band structure is not match at all with the literature data. where as cohesive energy and lattice constant is close to the experimental value. So please any one give me an idea that with same basis set and pseudopotential file both phases of (alpha and beta )tin are not reproducible ? What basis set and pseudopotential is suitable to calculate the beta phase of Sn ? Kindly suggest me what to do ? With best regards Suman K Sahoo Ph.D Student Deptt. of Chemistry Visva Bharati, Santiniketan India
