The results of transferability tests suggest that a Ti PP with only
3d
&input atom='Ti', dft='PBE', config='[Ar] 3d2 4s2 4p0', rlderiv=2.90, eminld=-4.0, emaxld=2.0, deld=0.01, nld=3, iswitch=3 / &inputp pseudotype=1, rho0=0.001, ... file_pseudopw='Ti.pbe-sp-rrkj.UPF' / 3 3S 1 0 2.00 0.00 1.1 1.1 3P 2 1 6.00 0.00 1.2 1.2 3D 3 2 2.00 0.00 1.3 1.3 &test configts(1)='3s2 3p6 3d2 4s2 4p0', /Note the presence of the &test namelist: it is used in this context to supply the electronic valence configuration, to be used for unscreening. As a first step, we do not include the core correction. In place of the dots we should specify the local reference potential. If we use lloc=-1 with large values of rcloc, (comparable to pseudization radii for the previous case) we get all kinds of mysterious errors:
from compute_chi : error # 1 n is too largefor rcloc=2.5, while rcloc=2.7 produces an equally mysterious
from run_pseudo : error # 1 Errors in PS-KS equationwhile smaller values (e.g. 1.5) lead to other errors:
WARNING! Expected number of nodes: 0 = 2-1-1, number of nodes found: 1.Even if the code doesn't stop, the presence of such messages is a signal of something going wrong in the generation algorithm. With some more experiments, though, one finds that rcloc=1.3 yields a good potential. We still have other choices. In this case, d
n l nl e AE (Ry) e PS (Ry) De AE-PS (Ry) 1 0 3S 1( 2.00) -4.60347 -4.60348 0.00001 2 1 3P 1( 6.00) -2.85621 -2.85623 0.00002 3 2 3D 1( 2.00) -0.31302 -0.31301 -0.00001 2 0 4S 1( 2.00) -0.32830 -0.32892 0.00062 3 1 4P 1( 0.00) -0.10777 -0.10732 -0.00045Note that the 3s
Cutoff (Ry) : 50.0 N = 1 N = 2 N = 3 E(L=0) = -4.5385 Ry -0.3263 Ry -0.0047 Ry E(L=1) = -2.8427 Ry -0.1071 Ry 0.0193 Ry E(L=2) = -0.1511 Ry 0.0311 Ry 0.0685 Ry Cutoff (Ry) : 100.0 N = 1 N = 2 N = 3 E(L=0) = -4.5883 Ry -0.3279 Ry -0.0048 Ry E(L=1) = -2.8547 Ry -0.1073 Ry 0.0193 Ry E(L=2) = -0.2918 Ry 0.0303 Ry 0.0649 Ry Cutoff (Ry) : 150.0 N = 1 N = 2 N = 3 E(L=0) = -4.5899 Ry -0.3280 Ry -0.0048 Ry E(L=1) = -2.8549 Ry -0.1073 Ry 0.0193 Ry E(L=2) = -0.2936 Ry 0.0303 Ry 0.0649 RyNote that for l = 0
$ grep Delta ld1.test dEtot_ps = 0.227291 Ry, Delta E= -0.001230 Ry dEtot_ps = 0.540886 Ry, Delta E= -0.000918 Ry dEtot_ps = 1.540155 Ry, Delta E= -0.002640 Ry dEtot_ps = 0.343314 Ry, Delta E= 0.000077 Ry dEtot_ps = 0.715061 Ry, Delta E= 0.001142 Ry dEtot_ps = 1.849816 Ry, Delta E= -0.000820 Ry dEtot_ps = 3.522904 Ry, Delta E= -0.004735 Ry dEtot_ps = 6.702626 Ry, Delta E= -0.003032 RyEnergy differences are reproduced with an error that does not exceed a few mRy (see column at the rhs). Eigenvalues are also well reproduced, e.g.:
1 0 3S 1( 2.00) -8.37382 -8.37230 -0.00152 2 1 3P 1( 6.00) -6.57173 -6.57195 0.00021 3 2 3D 1( 0.00) -3.84145 -3.83518 -0.00627 2 0 4S 1( 0.00) -2.73793 -2.74985 0.01192 3 1 4P 1( 0.00) -2.25938 -2.25525 -0.00412although errors may reach 0.01 Ry (still one order of magnitude better than what we get with the previous 4-electron PP). The price to pay is the presence of more electrons in the valence.