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## PseudoThis
keyword requests that a model potential be substituted for the core electrons.
The If
used with
## FULL ECP INPUT FORMATEffective Core Potential operators are sums of products of polynomial radial functions, Gaussian radial functions and angular momentum projection operators. ECP input therefore specifies which potential to use on each atomic center, and then includes a collection of triplets of: (coefficient, power of R, exponent) for each potential for each term in each angular momentum of the ECP. Since only the first few angular momentum components have different terms, the potential is expressed as (1) terms for the general case, typically d or f and higher projection, and (2) the extra terms for each special angular momentum. Thus for an LP-31G potential, which includes special s and p projected terms, the input includes the general (d and higher) term, the s-d term (i.e., what to add to the general term to make the s component) and the p-d term. All ECP input is free-format. Each block is introduced
by a line containing the center numbers (from the molecule specification) and/or
atomic symbols, specifying the atoms and/or atoms types to which it applies (just
as for general basis set input-see the discussion of the The pseudo-potential for those centers/atoms follows:
For
each component (
NTerm terms. NPower includes the R^{2}
Jacobian factor.An example of an input file which includes a nonstandard ECP with its associated basis set is given below. ## SIMPLIFIED ECP INPUT FORMAT
## KEYWORDS FOR STUTTGART/DRESDEN ECP INPUTIn
The Stuttgart/Dresden ECPs are not uniformly available across the periodic
table. The following table shows the availability of the various XY combinations,
along with valid values for
Note: These ECPs are not available for elements 87 (Fr), 88 (Ra), and 105 and higher
# HF/Gen Pseudo=Read Test Hydrogen peroxide 0,1 O H,1,R2 O,1,R3,2,A3 H,3,R2,1,A3,2,180.,0 R2=0.96 R3=1.48 A3=109.47
The basis set data follows the molecule specification section. The first line of the ECP data requests that a potential be read in (type 7) for atoms number 1 and 3 (the oxygen atoms) and that no potential is to be used for atoms 2 and 4 (the hydrogen atoms). The second line of ECP data begins the input for the first center
requiring a read-in potential, in this case oxygen atom 1. The potential on this
center is named
# Becke3LYP/Gen Pseudo=Read Opt Test HF/6-31G(d) Opt of Cr(CO)6 0 1 Cr 0.0 0.0 0.0 |