(2) Calculations of the band dispersion in the bcc structure, where the nonspin polarized collinear calculation with the lattice constant of 3.30 Ang. was performed using Nb_PBE19.vps, Nb7.0s3p2d2, and Nb7.0s3p3d3f1, and the origin of the energy is taken to be the Fermi level. The input file used for the OpenMX calculations can be found at NbbccBand.dat . For comparison the result by the Wien2k code is also shown, where the calculation was performed by default setting in the Ver. 10.1 of Wien2k except for the use of R_{MT} x K_{MAX} of 12.




Equilibrium bond length (Ang.)  Atomization energy (eV)  Atomization energy (couterpoise corrected) (eV)  




Nb9.0s3p2d2  2.164  4.16  4.15 
Nb9.0s3p3d3f1  2.120  4.48  4.45 
Other calc.  2.099^{a}  3.912 ^{a}   
Expt.  2.08 ^{b}  5.48 ^{b}   



