Note

This website is presently under development. The primary website for MOPAC is still http://openmopac.net until the majority of its contents have been migrated here.

VDW

In a COSMO calculation (keyword `ESP=78.4 <esp.html>`__), the Van der Waals radii of atoms can be set or changed by use of VDW. The format of the command is:

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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).

By default, the COSMO VdW radius is 117% of the default VdW radius.

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

Table 1: 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