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exercises:2014_ethz_mmm:basis_sets

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# Basis Sets

In this exericse you will compare different basis sets and use them for computing the binding energy of an H2 molecule.

The cp2k basis set format is the following:

Nsets
n1 lmin lmax Nexp Ncontr
exp1 contr1 contr2 contr3 ...
exp2 contr4 contr5 contr6 ...
Nexp....
n2 lmin lmax Nexp Ncontr
exp1 contr1 contr2 contr3 ...
exp2 contr4 contr5 contr6 ...
Nexp....
...

Nsets = number of sets.
n1,n2… = main quantum number (but it gets ignored by the program!)
lmin = min l (angular quantum number) of the set ( s = 0 ; p = 1 ; d = 2 …)
lmax = max l (angular quantum number) of the set ( s = 0 ; p = 1 ; d = 2 …)
Nexp = number of exponents of the set
Ncontr = number of contaction coefficients per angular quantum number

As an example:

      2                 2 Sets
1 0 0 1 1         Set 1: lmin=0 ; lmax=0 (→ s functions!) ; 1 exponent ; 1 contraction
0.35 1          exponent1 of  set 1 ; contraction
1 1 1 1 1         Set 2: lmin=1 ; lmax=1 (→ p functions!) ; 1 exponenet ; 1 contraction
0.6 1           exponent1 of set 2 ;  contraction