EM | ECM | ECMDL

[-]em|ecm|ecmdl   model-number

This keyword allows to specify the model for calculation of the electrostatic interaction energies.

The following models are available:

1. Numerical evaluation of the exact Coulomb integral, E_es
2. Spackman's model (2005): E_es = E_pro-pro + E_pro-def + E_def-def
3. Numerical evaluation of the exact Coulomb integrals E_pro-pro, E_pro-def, and E_def-def
4. Modified Spackman's model (for pseudoatoms only): E_es = E_sph-sph + E_sph-asph + E_asph-asph
5. Numerical evaluation of the exact Coulomb integrals E_sph-sph, E_sph-asph, and E_asph-asph (pseudoatoms only)
6. Spackman's model (1986)

Calculation of electrostatic interaction energies.

epmm  combines the exact potential (em 1) and mutipole methods (em > 1) for evaluation of intermolecular interaction energies.

ecd  allows entering the pathname of the disk file that contains specifications (i.e. keywords and options) for the calculation of molecular interaction energies, as an alternative to the usual command-line em specification.

1. "The use of the promolecular charge density to approximate the penetration contribution to intermolecular electrostatic energies"
   Mark A. Spackman
   Chemical Physics Letters 2005, 418, 154-158.

2. "Chemical Properties from the Promolecule"
   M.A. Spackman, E.N. Maslen
   J. Phys. Chem. 1986, 90, 2020-2027.

3. "Atom-atom potentials via electron gas theory"
   Mark A. Spackman
   J. Chem. Phys. 1986, 85, 6579-6586.

4. "A simple quantitative model of hydrogen bonding"
   Mark A. Spackman
   J. Chem. Phys. 1986, 85, 6587-6601.

5. "A simple quantitative model of hydrogen bonding. Application to more complex systems"
   Mark A. Spackman
   J. Phys. Chem. 1987, 91, 3179-3186.

6. "Energies of molecular interactions from Bragg diffraction data"
   M.A. Spackman, H.P. Weber, B.M. Craven
   J. Am. Chem. Soc. 1988, 110, 775-782.