C.1 Q-Chem Text Input Summary

C.1.5 Keyword: $ecp

(June 30, 2021)

$ecp
For each atom that will bear an ECP
      Chemical symbol for the atom
      ECP name; the L value for the ECP; number of core electrons removed
      For each ECP component (in the order unprojected, P^0, P^1, , P^L-1
            The component name
            The number of Gaussians in the component
            For each Gaussian in the component
                  The power of r; the exponent; the contraction coefficient
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$end

Note:  (1) All of the information in the $ecp block is case–insensitive. (2) The L value may not exceed 4. That is, nothing beyond G projectors is allowed. (3) The power of r (which includes the Jacobian r2 factor) must be 0, 1 or 2.