Vamp

http://www.accelrys.com/products/tsar/vamp.html

Vamp is a highly efficient semiempirical molecular orbital package. The programm has been optimised to produce very precise results extremely rapidly. Compatible with standard molecular modelling packages, Vamp easily integrates with your existing computational chemistry solution.

Current Version: V5.5 (SG, HP, IBM)

Applications

rapid calculation of optimised geometries and molecular orbitals
transition state searching and optimisation
accurate and reliable molecular electrostatic properties, potentials and fields
calculation of spectroscopic properties including ESR, NMR, IR and Raman frequencies, together with hyperpolarisabilities for non-linear optical studies
solvent effects and solvachromic shifts
simulation of environment using mixed quantum mechanical/classical mechanical model
precise structural optimisation
calculation of Natural Atomic Orbital Point Charges (NAO-PC)
calculation of spectra including solvent effects

The Vamp NAO-PC model provides an intermediate level between atom-centred charges and electron density calculations. The NAO-PC's give modelling systems a more detailed description of charges, electrostatic potential, polarisability and dispersion effects at the atomic level due to their anisotropic nature.

Vamp allows the effects of a molecule's environment to be considered by a number of methods. The solvent surrounding a molecule may be simulated to investigate the change produced in the energy and spectroscopic properties of the molecule. In addition, interactions with ordered environments (zeolites, enzymes, DNA) can be investigated using a mixed quantum mechanical and force field approach.

Vamp interfaces to Pro-Quantum for full data preparation and visualisation capabilities.