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pseudo-atomic basis orbitals Date: 2015/02/07 03:53 Name: Riemann   <riemann.derakhshan@gmail.com> Dear OpenMX users, I want to calculate a bandstructure for system which composed of Carbon, Hydrogen and gold atoms. I've copied this atoms pseudo-atomic basis orbitals information from openmx samples such as : <Definition.of.Atomic.Species C C5.0-s1p1 C_CA13 Au Au7.0-s2p2d2 Au_CA13 H H5.0-s2 H_CA13 Definition.of.Atomic.Species> but after running I've faced with wrong result and after checking other samples I've found that they aren't constant and depend on the structure and the other things. for example for Carbon atom I've found this two forms, C C5.0-s1p1 and C C5.0-s2p2 , now I amconfused about it. I want to know how I can find proper choise of pseudo-atomic basis orbitals for my considered system? Sincerely Riemann

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Re: pseudo-atomic basis orbitals ( No.1 ) Date: 2015/02/10 21:38 Name: T. Ozaki Hi, When we start calculations for new systems, we always check how results depends on the choice of basis functions by taking a simple typical system whose chemical environment is similar to that of the systems we are interested in. For carbon, for instance, we may try the following basis sets C5.0-s2p1 C5.0-s2p2 C5.0-s2p2d1 C5.0-s3p2d2 and see how the band structure and structural parameters change. The proper choice of basis functions can be guessed from the eigenvalues tabulated in C5.0.pao http://www.jaist.ac.jp/~t-ozaki/vps_pao2013/C/C5.0.pao such as *************************************************** Eigen values(Hartree) of pseudo atomic orbitals *************************************************** Eigenvalues Lmax= 3 Mul=15 l mu 0 0 -0.76319822980011 l mu 0 1 0.18909670680934 l mu 0 2 1.27862516448425 l mu 0 3 2.83941603744602 l mu 0 4 4.79556925519831 l mu 0 5 7.11242201748510 l mu 0 6 9.82151407410562 l mu 0 7 12.96909315820673 l mu 0 8 16.55835459985843 l mu 0 9 20.56979153896505 l mu 0 10 24.99657501398784 l mu 0 11 29.84563149254775 l mu 0 12 35.12045242674265 l mu 0 13 40.81728662023897 l mu 0 14 46.93395086153954 l mu 1 0 -0.43927241740560 l mu 1 1 0.29948357024387 l mu 1 2 1.34575456628730 l mu 1 3 2.87842764976528 l mu 1 4 4.88945224528083 l mu 1 5 7.36680566251138 l mu 1 6 10.28984755015475 l mu 1 7 13.63826992073707 l mu 1 8 17.40500439924996 l mu 1 9 21.59658606906815 l mu 1 10 26.21955912501341 l mu 1 11 31.27152086490978 l mu 1 12 36.74657604654949 l mu 1 13 42.64330246824836 l mu 1 14 48.96387191819690 l mu 2 0 0.31861248802749 l mu 2 1 1.15335473535849 l mu 2 2 2.44837554435501 l mu 2 3 4.19574909929819 States with lower eigenvalues should be given priority in the choice. Also a paper (Phys. Rev. B 69, 195113 (2004)) may be helpful for this consideration. Best regards, TO

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