# BASIS

Section can be repeated.

Section used to specify a general basis set for QM calculations. [Edit on GitHub]

## Keywords

- SECTION_PARAMETERS

- DEFAULT_KEYWORD

## Keyword descriptions

SECTION_PARAMETERS: string = Orbital

  Lone keyword: `Orbital`

  Usage: Orbital

  The type of basis set defined in this section. [Edit on GitHub]

DEFAULT_KEYWORD: string

  Keyword can be repeated.

  CP2K Basis Set Standard Format:

      Element symbol  Name of the basis set  Alias names
      nset (repeat the following block of lines nset times)
      n lmin lmax nexp nshell(lmin) nshell(lmin+1) ... nshell(lmax-1) nshell(lmax)
      a(1)      c(1,l,1)      c(1,l,2) ...      c(1,l,nshell(l)-1)      c(1,l,nshell(l)), l=lmin,lmax
      a(2)      c(2,l,1)      c(2,l,2) ...      c(2,l,nshell(l)-1)      c(2,l,nshell(l)), l=lmin,lmax
       .         .             .                 .                       .
       .         .             .                 .                       .
       .         .             .                 .                       .
      a(nexp-1) c(nexp-1,l,1) c(nexp-1,l,2) ... c(nexp-1,l,nshell(l)-1) c(nexp-1,l,nshell(l)), l=lmin,lmax
      a(nexp)   c(nexp,l,1)   c(nexp,l,2)   ... c(nexp,l,nshell(l)-1)   c(nexp,l,nshell(l)), l=lmin,lmax

      nset     : Number of exponent sets
      n        : Principle quantum number (only for orbital label printing)
      lmax     : Maximum angular momentum quantum number l
      lmin     : Minimum angular momentum quantum number l
      nshell(l): Number of shells for angular momentum quantum number l
      a        : Exponent
      c        : Contraction coefficient

[Edit on GitHub]