Difference between revisions of "The cohesive energy of Iron"
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is defined as (for a two atom cell). | is defined as (for a two atom cell). | ||
<math> E_{coh}(Fe)=\frac{1}{2}(E_{bulk}-2E_{iso}) < | <math> E_{coh}(Fe)=\frac{1}{2}(E_{bulk}-2E_{iso}) </math> | ||
The differnece between this and our silicon example is that here we: | The differnece between this and our silicon example is that here we: | ||
a) turn on colinear magnetism | a) turn on colinear magnetism.// | ||
b) we manually cycle through the spin states setting the differemce between the up and down to an integer, <math>n</math>.// | b) we manually cycle through the spin states setting the differemce between the up and down to an integer, <math>n</math>.// | ||
c) the lowest energy spin stae is the one we use for the above calculation. | c) the lowest energy spin stae is the one we use for the above calculation. | ||
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nspin=2 | nspin=2 | ||
Nupdown=<math>n</math> | Nupdown=<math>n</math> | ||
Bulk | |||
nupdown=1 Etot=-.15545381E+02 | |||
nupdown=2 Etot=-.15828724E+02 | |||
nupdown=3 Etot=-.16184416E+02 | |||
nupdown=4 Etot=-.16498563E+02 | |||
nupdown=5 Etot=-.16460255E+02 | |||
nupdown=6 Etot=-.15868657E+02 | |||
Isolated | |||
==crystal17 settings== | ==crystal17 settings== | ||
Latest revision as of 18:06, 11 February 2022
The cohesive energy of Fe is a good example of a "spin" system. This system is colinear which means we can consider electrons either polarised as spin up or spin down.
Like before, the cohesive enerfy v is defined as (for a two atom cell).
The differnece between this and our silicon example is that here we: a) turn on colinear magnetism.// b) we manually cycle through the spin states setting the differemce between the up and down to an integer, .// c) the lowest energy spin stae is the one we use for the above calculation.
Vasp settings
nspin=2 Nupdown=
Bulk nupdown=1 Etot=-.15545381E+02 nupdown=2 Etot=-.15828724E+02 nupdown=3 Etot=-.16184416E+02 nupdown=4 Etot=-.16498563E+02 nupdown=5 Etot=-.16460255E+02 nupdown=6 Etot=-.15868657E+02
Isolated