- Development of models -
Structure and Thermodynamics

The present-day version of the Consistent Force Field, CFF, was developed at Department of Chemistry of the

The CFF belongs to the group of methods called molecular mechanics where the potential energy of a molecule, a molecular complex or a crystal is calculated as a sum of inter-atomic potentials, whose parameters are ideally obtained by optimization on experimental structural and spectroscopic data for the pure substances. A set of parameters is called a force field.

It is a tool with which you can develop force fields, in the sense that you can optimize the parameters of potential energy functions on several categories of data for molecules in gaseous and crystalline states.

The imbedded methods allow for calculation of molecular properties such as conformations, vibrational frequencies and thermodynamic functions. The integrated optimisation facility is unique and fundamental to the CFF concept.

The most important technical contributions from the Danish group are: weighted Levenberg-Marquardt optimization, a crystal simulator using Ewald sums and an interactive graphical interface to the optimization algorithm GOPT (Graphics OPtimization Tool).

The uniqueness of CFF is found in its optimization capabilities. At present CFF can optimize on bond lengths, valence angles, torsional angles, out-of-plane angles, non-bonded distances, unit cell dimensions, lattice energies, molecular potential energies, dipole moments, and vibrational frequencies.

Force fields based on theoretical data obtained from large-scale *ab initio* calculations at the MP2 level or employing DFT to include electron correlation are currently being optimised.

Applications of CFF are numerous:
coordination compounds;
saccharides;
aluminosilicates;
intermolecular interactions and phase equilibria.

**Selected general references**

On special occasions, and if schedules permit, a lecture
of an historical character can be offered.

A lecture *in Danish* on *former and current principles of molecular modelling* was given in April 2004 at Roskilde University. The text, with illustrations, is available.
Right-click
to open the .pdf file. This lecture, and others, may also be found *via* the Model Day homepage

**Course** related to
CFF .

A Ph. D. course aiming specifically at force field development through optimisation of potential energy function parameters has been developed :
Force Field Development for Molecular Modelling.

Both courses will be renewed from time to time.

Dr. techn. * Kjeld Rasmussen, R*, Reader (retired)

Photo is from July 2004.

This is from June 2004, 50 years after I donned my student's cap.

Photos from the 50 y festivities are decidedly for the old boys and girls,

and are not of interest to others.

Telephone: + 45 39 69 18 13

Email:

Curriculum Vitae: short; complete; complete in Danish

List of publications: shortened; complete

My wife

We also are rodeo afficionados and have attended several rodeos in Arkansas and Colorado.

Fornyet 20-10-2004