pseudopotential
This option defines the pseudopotentials used for quantum chemistry calculations. You can define pseudopotentials in several flexible ways.
- Using Built-in Pseudopotentials
- Explicit Pseudopotential Definitions
- Using Self-defined Pseudopotential Files
pseudopotential
only contains pseudopotential and does not contain any valence electron basis set information. You must assign basis sets in basis
. The valence basis and core pseudopotential must match.
Below is a typical example. H is represented by a def2-TZVP basis set. For Au, the valence electrons are represented by a def2-TZVP basis set, and core electrons are repesented by def2-ecp, i.e. Stuggart-Cologne pseudopotential.
basis
def2-TZVP
end
pseudopotential
def2-ecp
end
# The Karlsruhe basis sets for Au was developed with Stuggart-Cologne pseudopotential.
mol
Au 0. 0. 0. # SDD+def2-TZVP
H 0. 0. 1. # def2-TZVP
end
If you write it in this way:
# A wrong input!
basis
def2-TZVP
end
mol
Au 0. 0. 0.
H 0. 0. 1.
end
Then, no pseudopotential is applied for any element!
Also, keep in mind that the valence basis and core pseudopotential must match. The following combinations are usually accepted:
Valence Basis Set | Pseudopotential |
---|---|
def2-X | def2-ecp |
(aug-)cc-X-pp | cc-ecp |
lanlX | lanl-ecp |
Using Built-in Pseudopotentials
A lot of important pseudopotentials have been provided in a folder pseudopotential
in the same path of Qbics. The files are named after their names well-known in computational chemistry community. For example, pseudopotential/def2-ecp
contains the Stuggart-Cologne pseudopotentials. All files are named in small cases.
To use them, simple write down the basis set name. It is case-insensitive. For example, to use def2-ecp:
pseudopotential
def2-ecp
end
Qbics will extract pseudopotential information from pseudopotential/def2-ecp
for all atoms that have pseudopotentials. For example, you molecule contains only C, H, N, Ce, and F. Since in pseudopotential/sdd
, there is only pseudopotential for Ce, then for C, H, N, and F, no pseudopotentials are applied.
Explicit Pseudopotential Definitions
You can also explicitly define your pseudopotentials. For example, you want to apply pseudopotentials for Rb and Sr, then their pseudopotentials can be defined in this way:
pseudopotential
RB 0
RB-ECP 3 28
f POTENTIAL
1
2 3.84311400 -12.31690000
s-f POTENTIAL
3
2 5.03655100 89.50019800
2 1.97084900 0.49376100
2 3.84311400 12.31690000
p-f POTENTIAL
3
2 4.25834100 58.56897400
2 1.47070900 0.43179100
2 3.84311400 12.31690000
d-f POTENTIAL
3
2 3.02312700 26.22489800
2 0.65038300 0.96283900
2 3.84311400 12.31690000
****
SR 0
SR-ECP 3 28
f POTENTIAL
1
2 4.63397500 -15.80599200
s-f POTENTIAL
3
2 7.40007400 135.47943000
2 3.60637900 17.53446300
2 4.63397500 15.80599200
p-f POTENTIAL
3
2 6.48486800 88.35970900
2 3.28805300 15.39437200
2 4.63397500 15.80599200
d-f POTENTIAL
3
2 4.62284100 29.88898700
2 2.24690400 6.65941400
2 4.63397500 15.80599200
****
end
The pseudopotential definition is of standard Gaussian94 format:
- The definition of the pseudopotential for each atom ends with 4 asterisks, i.e.
****
. - The definition starts with the element name like
Rb
and a0
. Currently0
has no meaning. - Then, three parameters are given: pseudopotential name, maximum angular momentum, and number of core electrons.
- Then, the semi-local pseudopotential and local ones are listed. Each pseudopotential has the form :
- The first line is a comment.
- The contraction degree .
- Then, each line defines the power , the exponent , and the contraction coefficient . They are 3 real numbers.
Note that many pseudopotentials in Gaussian94 format can be obtained from https://www.basissetexchange.org/. But, remember to replace D
to E
since the former is not recognized by Qbics. Also, add ****
between elements.
Using Self-defined Pseudopotential Files
You can also put your explicit pseudopotential definitions into some files, say /home/zhang/userdef/my-own-pseudopotential
. Qbics will automatically read it if you give explicit file name including path.
pseudopotential
/home/zhang/userdef/my-own-pseudopotential
end