Quantum Mechanics with HyperChem

Quantum Mechanics

HyperChem software provides versatile tools for exploring the structure, stability and properties of molecules using quantum mechanics. There are simple ways to produce 3D molecular structures on screen. You choose from nine semi-empirical methods, and you can use geometry optimizers to search for stable structures or molecular dynamics techniques to model sample reaction trajectories. HyperChem allows you to easily add to or modify the semi-empirical quantum mechanics parameters in text files.

With HyperChem, you can perform semi-empirical calculations on elements hydrogen through xenon, including transition-metals. HyperChem includes a model builder that turns a rough 2D sketch of a molecule into 3D. HyperChem combines semi-empirical quantum mechanics and molecular mechanics methods in a single package to create a powerful tool for finding better starting geometries, substantially reducing computation time.

Quantum Mechanics Applications

HyperChem quantum mechanical methods have many practical applications to the study of molecular structure and properties, including:

Determining frontier orbital interactions between donor and acceptor molecules as illustrated by Diels-Alder cycloaddition reactions.
Obtaining partial atomic charges, using Mulliken population analysis, to predict likely sites of attack.
Generating electrostatic potential contour plots to illustrate likely trajectories of approach in drug-receptor docking.
Calculating unpaired spin densities to identify possible reactive sites on a molecule or for correlation with ESR data.

UV-Visible Spectroscopy

Predict wavelengths and intensities of electronic transitions.
Predict locations of non-spectroscopically active states.

IR Spectroscopy

Predict wave numbers and intensities of vibrational absorption lines.
Display motions of normal modes using vectors and animations.

Nine Semi-Empirical Methods

HyperChem includes nine semi-empirical quantum-mechanical methods that are implementations of methods developed and published by respected research groups. These methods range from the simple all-valence-electron method (Extended Hückel) to among the most sophisticated and accurate semi-empirical methods currently available (AM1 and PM3).

The semi-empirical quantum mechanics methods available in HyperChem software are:

Extended Hückel, developed by R. Hoffmann.
CNDO and INDO, developed by the research group lead by J. A. Pople.
MINDO/3, MNDO and AM1, developed by the research group of M. J. S. Dewar.
PM3, developed by J. J. P. Stewart.
ZINDO/1 and ZINDO/S developed by the research group led by M. Zerner.

Flexible and Powerful

Several options for electronic structure calculations are available:

Systems with any charge and with spin multiplicity up to four can be studied.
Restricted and Unrestricted Hartree-Fock (RHF/UHF)calculations on closed-shell and open-shell systems can be performed.
Ground states (for each spin multiplicity), and first excited singlet state can be calculated.
Configuration Interaction (CI) using orbital or energy criteria with singles only or microstate methods.
The number of atoms is limited only by the memory in your PC: calculations using over 200 atomic orbitals can be carried out on a PC with 4Mb of RAM.

You can obtain a variety of useful results with these calculations, including:

Contour plots of molecular orbitals, charge and spin densities, and electrostatic potential.
Displays of orbital energy-level diagrams.
A log file of numerical data, including energies, heats of formation (for NOO methods), dipole moments, molecular orbital coefficients, and the density matrix.
Plots and log file data that allow you to study chemical reactivity and heats of formation.

[Products] [Sales] [Support] [Science] [News] [Corporate] [Search] [Home]