AMPAC Features

New & Improved in AMPAC 10

New in AGUI

Speed

Rock Solid Reliability

More robust than any competing product for all calculations, including SCF convergence, geometry optimizations, transition state location, frequencies, solvation and C.I.

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Features

AMPAC is not only faster and more reliable, it has a much wider range of capabilities that that "other guy".
Extensive Documentation
Comprehensive manual providing descriptions of all input, examples, discussion of all methods and literature references in html and pdf formats.
Feature-Rich Industry-Leading Graphical Interface
AGUI has also been updated and improved, and is optimized for quantum mechanical calculations.

Active Maintenance and Development

AMPAC (along with AGUI) is constantly being improved in response to customer feedback and needs, market demands, new methods, and the interests of our own researchers and collaborators.

Semiempirical Models

Calculation Types

Energies, optimizations, frequencies, relaxed PES scans, transition state and intermediate searches, annealing, IRCs.

Solvation

Treatment of solvated systems using COSMO or several of the AMSOL models from Truhlar and Cramer, which are now included at no additional cost! Our CI engine has been integrated with both of these solvation methods, a unique capability.
Configuration Interaction (C.I.)
Fast and robust, handling singlets (S), singlets-doublets (SD), singlest-doublets-triplets (SDT) or complete active space (CAS) within any set of MOs. AMPAC's CI can be used for all calculation types with open shell systems and/or excited states. Also, AMPAC's C.I. implementation of gradients is fully analytical (not numerical) for much better results that are vastly faster and more stable.

Excited States

Calculate excited state geometries and corresponding properties. Computes vertical transition energies, transition dipole moments and oscillator strengths from the ground state to any number of excited states using our advanced configuration interaction (CI) methods.

Transition States and Intermediates

Advanced CHN and FULLCHN methods for locating intermediates and transition states along a single- or multi-step reaction path specified by two or more input geometries.

Multiple Minima Searches

Fully-customizable simulated annealing to automatically find multiple minima (conformers, structural isomers) or other critical points (i.e. transition states).

Robust Optimization Methods

Efficient and robust geometry optimizations (constrained or unconstrained) in Z-matrix or Cartesian coordinates. Both gradient-based or Hessian-based energy minimization methods (TRUSTE and NEWTON) are available for energy minima. Energy/gradient minimization methods (TRUSTG and LTRD) are available for local transition states.

Fast Stationary Point Characterizations

Innovative LFORCE and HESSEI methods for fast, accurate characterization of stationary points without the need for full frequency calculations.

PES Scans

Relaxed scanning of potential energy surfaces using one or two geometric coordinates

Intrinsic Reaction Paths

Integration of intrinsic reaction paths from transition states to products and reactants using IRC or PATH methods.

Properties

Heats of formation, other thermodynamic properties, vibrational spectra, dipole moments, polarizabilities and hyperpolarizabilities, electronic spectra, ESR, charge distributions, bond orders, and unpaired spin denisties.

Atomic Charges

Excited States

Calculate excited state geometries and corresponding properties and compute vertical transition energies, transition dipole moments and oscillator strengths from the ground state to any number of excited states using our advanced configuration interaction (CI) methods. The CI implementation in AMPAC is fully analytical, greatly improving both speed and stability.

QSAR Output

Simple generation of all output used by the CODESSA QSAR package, via the "CODESSA" keyword.

Batch Execution

Submit multiple AMPAC input files and request AMPAC 8 to automatically run then in sequence.