[Wien] why only 1 k-point is used

[Stefaan Cottenier]

>    I get the method of calculating the cohesive energy from WIEN2k-FAQ,but why only 1 k-point is used while other parameters are identical? Is it just because difficult to converge?
>
Free atom = big and almost empty unit cell = very small reciprocal 
lattice unit cell = sufficiently densely sampled by just 1 k-point.

Or in other words: there is no dispersion for a free atom, and then 
obviously you need to know the eigenvalues just at one k-point.

Stefaan


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