TOMBO Ver.2 Manual

5.1 LDA calculation of isolated dimers 51
Figs. 5.2(a) and (b) represent the force and total energy of iron dimer (Fe 2 ) in the LSDA
calculations with and without the spherical cut of Coulomb potential. In both calculations,
unit cell is simple cubic, "nspin=6", and "Fe_rct=1.00". The lattice constant is 12 [Å] (6.8
[Å]) and "nod=17" ("nod=10") corresponding to the PW cut-off energy of 22.2 [Ry] (23.9
[Ry]) for the calculation with (without) the spherical cut. The two results with and without
the spherical cut are slightly different. There is a minimum of the total energy at distance
2.00 [Å] (1.97 [Å]), where the Force crosses zero.
(a) with spherical cut
(b) without spherical cut
Fig. 5.2 Force and total energy of iron dimer (Fe 2 ) versus bond length in a calculation with
and without spherical cut.
Figs. 5.3(a) and (b) represent the force and total energy of iron dimer (Ni 2 ) in the LSDA
calculations with and without the spherical cut of Coulomb potential. In both calculations,
unit cell is simple cubic, "nspin=2", and "Ni_rct=1.00". The lattice constant is 12 [Å] (6.8
[Å]) and "nod=17" ("nod=10") corresponding to the PW cut-off energy of 22.2 [Ry] (23.9
[Ry]) for the calculation with (without) the spherical cut. The two results with and without
the spherical cut are slightly different. There is a minimum of the total energy at distance
2.03 [Å] (2.01 [Å]), where the Force crosses zero.