Pseudo

DESCRIPTION

This keyword requests that a model potential be substituted for the core electrons. The Cards option is by far its most-used mode. Gaussian supports a new effective core potential (ECP) input format (similar to that used by ExtraBasis) which is described below. When reading-in pseudopotentials, do not give them the same names as any internally-stored pseudopotentials: CEP, CHF, LANL1, LANL2, LP-31, SDD and SHC.

If used with ONIOM, the Pseudo keyword applies to all layer of the ONIOM. If you want to read in ECPs only for one ONIOM layer, then use the GenECP keyword instead.

Pseudo without any options defaults to Pseudo=Read.

OPTIONS

Read
Read pseudopotential data from the input stream. Input is described in the next subsection below. Cards is a synonym for Read.

Old
Read pseudopotential data using the old format (used by Gaussian 92 and earlier versions).

CHF
Requests the Coreless Hartree-Fock potentials. This option is normally used with the LP-31G basis sets.

SHC
Requests the SHC potentials.

LANL1
Requests the LANL1 potentials.

LANL2
Requests the LANL2 potentials.

FULL ECP INPUT FORMAT

Effective 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 Gen keyword). The list ends with a value of 0.

The pseudopotential for those centers/atoms follows:

Name,Max,ICore
Name of the potential, maximum angular momentum of the potential (i.e., 2 if there are special s and p projections, 3 if there are s, p, and d projections), and number of core electrons replaced by the potential. If Name matches the name of a previous potential, that potential is reused and no further input other than the terminator line (see below) is required.

For each component (I=1 to Max) of the current potential, a group of terms is read, containing the following information:

Title
A description of the block, not otherwise used.

NTerm
Number of terms in the block.

NPower,Expon,Coef
Power of R, exponent, and coefficient for each of the NTerm terms. NPower includes the R2 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

Gaussian adds flexibility to ECP input by allowing it to include pre-defined basis sets names. An ECP definition may be replaced by a line containing the standard keyword for a pre-defined basis set. In this case, the ECPs within the specified basis set corresponding to the specified atom type(s) will be used for that atom (see the examples).

KEYWORDS FOR STUTTGART/DRESDEN ECP INPUT

In Pseudo input, keywords for these ECPs are of the form XYn where n is the number of core electrons which are replaced by the pseudopotential and X denotes the reference system used for generating the pseudopotential (S for a single-valence-electron ion or M for a neutral atom).

Y specifies the theoretical level of the reference data: HF for Hartree-Fock, WB for Wood-Boring quasi-relativistic and DF for Dirac-Fock relativistic. For one- or two-valence electron atoms SDF is a good choice; otherwise MWB or MDF is recommended (although for small atoms or for the consideration of relativistic effects, the corresponding SHF and MHF pseudopotentials may be useful).

AVAILABILITY

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 n. The Defaults columns list the equivalencies for the SDD keyword (which selects an all electron basis set through Cl and ECPs thereafter) and when IOp(3/6) is set to 6 (which selects ECPs for all elements).

    Valid values of n for given values of X and Y
Atom     Defaults    MWB    SDF    SHF    MDF    MHF
    IOp(3/6=6)    SDD keyword                        
1    H    D95    D95                        
2    He    D95    D95                        
3    Li    SDF2    D95                        
4    Be    SDF2    D95         2              
5    B    MWB2    D95    2    2              
6    C    MWB2    D95    2    2              
7    N    MWB2    D95    2    2              
8    O    MWB2    D95    2    2              
9    F    MWB2    D95    2    2              
10    Ne    MWB2    D95    2                   2
11    Na    SDF10    6-31G         10              
12    Mg    SDF10    6-31G         10              
13    Al    MWB10    D95    10    10              
14    Si    MWB10    D95    10    10              
15    P    MWB10    D95    10    10              
16    S    MWB10    D95    10    10              
17    Cl    MWB10    D95    10    10              
18    Ar    MWB10    6-31G    10                   10
19    K    MWB10    MWB10    10    18    18         
20    Ca    MWB10    MWB10    10    18    18         
21    Sc    MDF10    MDF10                   10    10
22    Ti    MDF10    MDF10                   10    10
23    V    MDF10    MDF10                   10    10
24    Cr    MDF10    MDF10                   10    10
25    Mn    MDF10    MDF10                   10    10
26    Fe    MDF10    MDF10                   10    10
27    Co    MDF10    MDF10                   10    10
28    Ni    MDF10    MDF10                   10    10
29    Cu    MDF10    MDF10              28    10    10
30    Zn    MDF10    MDF10    28    28         10    10
31    Ga    MWB28    MWB28    28    28              
32    Ge    MWB28    MWB28    28    28    28         
33    As    MWB28    MWB28    28    28              
34    Se    MWB28    MWB28    28    28              
35    Br    MWB28    MWB28    28    28              
36    Kr    MWB28    MWB28    28                   28
37    Rb    MWB28    MWB28    28    36    36         
38    Sr    MWB28    MWB28    28    36    36         
39    Y    MWB28    MWB28    28                   28
40    Zr    MWB28    MWB28    28                   28
41    Nb    MWB28    MWB28    28                   28
42    Mo    MWB28    MWB28    28                   28
43    Tc    MWB28    MWB28    28                   28
44    Ru    MWB28    MWB28    28                   28
45    Rh    MWB28    MWB28    28                   28
46    Pd    MWB28    MWB28    28                   28
47    Ag    MWB28    MWB28    28         46         28
48    Cd    MWB28    MWB28    28                   28
49    In    MWB46    MWB46    46    46              
50    Sn    MWB46    MWB46    46    46              
51    Sb    MWB46    MWB46    46    46              
52    Te    MWB46    MWB46    46    46              
53    I    MWB46    MWB46    46    46         46    
54    Xe    MWB46    MWB46    46                   46
55    Cs    MWB46    MWB46    46    54    54         
56    Ba    MWB46    MWB46    46    54              
57    La    MWB28    MWB28    28, 46, 47                   46, 47
58    Ce    MWB28    MWB28    28, 47, 48                   47, 48
59    Pr    MWB28    MWB28    28, 48, 49                   48, 49
60    Nd    MWB28    MWB28    28, 49, 50                   49, 50
61    Pm    MWB28    MWB28    28, 50, 51                   50, 51
62    Sm    MWB28    MWB28    28, 51, 52                   51, 52
63    Eu    MWB28    MWB28    28, 52, 53                   52, 53
64    Gd    MWB28    MWB28    28, 53, 54                   53, 54
65    Tb    MWB28    MWB28    28, 54, 55                   54, 55
66    Dy    MWB28    MWB28    28, 55, 56                   55, 56
67    Ho    MWB28    MWB28    28, 56, 57                   56, 57
68    Er    MWB28    MWB28    28, 57, 58                   57, 58
69    Tm    MWB28    MWB28    28, 58, 59                   58, 59
70    Yb    MWB28    MWB28    28, 59                   59
71    Lu    MWB60    MWB60    28, 60                   60
72    Hf    MWB60    MWB60    60                   60
73    Ta    MWB60    MWB60    60                   60
74    W    MWB60    MWB60    60                   60
75    Re    MWB60    MWB60    60                   60
76    Os    MWB60    MWB60    60                   60
77    Ir    MWB60    MWB60    60                   60
78    Pt    MWB60    MWB60    60                   60
79    Au    MWB60    MWB60    60         78    60    60
80    Hg    MWB60    MWB60    60, 78              60    60, 78
81    Tl    MWB78    MWB78    78                   78
82    Pb    MWB78    MWB78    78                   78
83    Bi    MWB78    MWB78    78                   78
84    Po    MWB78    MWB78    78                   78
85    At    MWB78    MWB78    78                   78
86    Rn    MWB78    MWB78    78                   78
89    Ac    MWB60    MWB60    60                   60
90    Th    MWB60    MWB60    60                   60
91    Pa    MWB60    MWB60    60                   60
92    U    MWB60    MWB60    60                   60
93    Np    MWB60    MWB60    60                   60
94    Pu    MWB60    MWB60    60                   60
95    Am    MWB60    MWB60    60                   60
96    Cm    MWB60    MWB60    60                   60
97    Bk    MWB60    MWB60    60                   60
98    Cf    MWB60    MWB60    60                   60
99    Es    MWB60    MWB60    60                   60
100    Em    MWB60    MWB60    60                   60
101    Md    MWB60    MWB60    60                   60
102    No    MWB60    MWB60    60                   60
103    Lr    MWB60    MWB60    60                   60
104    Rf                             92    

Note: These ECPs are not available for elements 87 (Fr), 88 (Ra), and 105 and higher.

RELATED KEYWORDS

ChkBasis, ExtraBasis, Gen, GenECP

EXAMPLES

Specifying an ECP. This input file runs an RHF/LP-31G calculation on hydrogen peroxide, with the basis set and ECP data read from the input file:

# 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
 
General basis set input
****
 
O 0                        ECPs for the oxygen atoms.
OLP 2 2                    ECP name=OLP, applies to d & higher, replaces 2 electrons.
D component                Description for the general terms.
3                          Number of terms to follow.
1 80.0000000  -1.60000000
1 30.0000000  -0.40000000
2  1.0953760  -0.06623814
S-D projection             Corrections for projected terms (lowest angular momentum).
3
0  0.9212952   0.39552179
0 28.6481971   2.51654843
2  9.3033500  17.04478500
P-D                        Corrections for projected terms (highest angular momentum).
2
2 52.3427019  27.97790770
2 30.7220233 -16.49630500 
                           Blank line indicates end of the ECP block.

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). 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 centers requiring a read-in potential: in this case, oxygen atoms. The potential on these centers is named OLP, it is a general term and applies to angular momentum 2 (d) and higher, and the potential replaces two electrons. Next comes a title for the general term (D component), and the number of components of that term (3); the individual components follow on the next 3 lines. Next come the corrections for the projected terms in two sections, lowest angular momentum first. Each section again consists of a title line, the number of terms to follow, and then the terms themselves.

Using Standard Basis Set Keywords to Specify ECPs. The following input file illustrates the use of the simplified ECP input format:

# Becke3LYP/Gen Pseudo=Read Opt Test
 
HF/6-31G(d) Opt of Cr(CO)6
 
0 1
Cr 0.0  0.0  0.0
molecule specification continues …
 
C O 0
6-31G(d)
****
Cr 0
LANL2DZ
****
 
Cr 0                                  ECP for chromium atom.
LANL2DZ                               Use the ECP in this basis set.

 

Last update: 23 April 2013