VDW(text)

The Van der Waals radii of atoms can be set or changed by use of VDW. The format of the command is:

VDW(:<chemical symbol1>=n.nn:<chemical symbol2>=n.nn:<chemical symbol3>=n.nn:...)

For example, VDW(:Cl=2.33:Br=2.50) would override the default values of the van der Waals radii of chlorine and bromine (1.65 and 1.80, respectively). Note that all chemical symbols (including the first one) must be preceded by a colon (:).

This keyword is used in setting the VDW radii in the COSMO solvation method, and the ESP and PMEP  electrostatic methods.

By default, the COSMO VdW radius is 117% of the default VdW radius.
By default, the MEP VdW radius is the default VdW radius.
There is no default PMEP radius.

 Table 1: Default radii (Angstroms)

I

II

Transition Metals

 

 

III

IV

V

VI

VII

 VIII

H

1.20

 

 

He

1.40

Li

1.82

Be

1.87

B

1.69

C

1.70

N

1.55

O

1.52

F

1.47

Ne

1.54

Na

2.27

Mg

1.73

Al

2.06

Si

2.10

P

1.80

S

1.80

Cl

1.75

Ar

1.88

K

2.75

Ca

2.17

Sc

2.26

Ti

2.26

V

2.15

Cr

2.05

Mn

2.10

Fe

2.06

Co

2.05

Ni

1.63

Cu

1.40

Zn

1.39

Ga

1.87

Ge

2.10

As

1.85

Se

1.90

Br

1.85

Kr

2.02

Rb

3.23

Sr

2.94

Y

2.90

Zr

2.85

Nb

2.80

Mo

2.20

Tc

2.20

Ru

2.20

Rh

2.20

Pd

1.63

Ag

1.72

Cd

1.58

In

1.93

Sn

2.17

Sb

2.16

Te

2.06

I

1.98

Xe

2.16

Cs

3.42

Ba

2.97

La

2.40

Hf

2.20

Ta

2.20

W

2.20

Re

2.20

Os

2.20

Ir

2.20

Pt

1.75

Au

1.66

Hg

1.55

Tl

1.96

Pb

2.02

Bi

2.26

 

 

 

Where radii specific for various methods is available, they are used.  Radii available are:

 Table 2: Default radii (Angstroms) used in ESP, and PMEP

I

II

  

III

IV

V

VI

VII

 VIII

H

1.20

 

 

He

1.20

Li

1.37

Be

1.45

B

1.45

C

1.50

N

1.50

O

1.40

F

1.35

Ne

1.30

Na

1.57

Mg

1.36

Al

1.24

Si

1.17

P

1.80

S

1.75

Cl

1.70

  

K
 

Ca
 

 

Transition Metals
(none)

 

Ga

Ge

As

Se

Br
1.80

  

Rb

Sr

In

Sn

Sb

Te

I

  

Cs

Ba

Tl

Pb

Bi

 

 

  

Table 3: Default radii (Angstroms) used in COSMO

I

II

 

III

IV

V

VI

VII

H
1.08

 

 

Li
1.80

Be

B

C
1.53

N
1.48

O
1.36

F
1.30

Na
2.30

Mg

Al
2.05

Si
2.10

P
1.75

S
1.70

Cl
1.65

K
2.30

Ca
2.75

 

Transition Metals
(none)

Ga

Ge

As

Se

Br
1.80

Rb

Sr

In

Sn

Sb

Te

I
2.05

Cs

Ba

Tl

Pb

Bi