Spartan 5.1 User's Guide

Appendix B: Units Used in Spartan

Geometry

    Bond distances are given in Ångstroms (Å) and bond angles and dihedral angles in degrees (°).

    Surface areas are given in (Ångstroms)2 and volumes in (Ångstroms)3.

    1 Ångstrom = 1.889762 atomic units

Energies, Heats of Formation and Strain Energies

    Total energies from ab initio and density functional calculations are typically given in atomic units (also termed hartrees), but are also available in kcal/mol and in kJ/mol.

    Heats of formation from semi-empirical calculations are typically given in kcal/mol, but are also available in atomic units (hartrees) and in kJ/mol.

    Strain energies from molecular mechanics calculations are typically given in kcal/mol, but are also available in atomic units (hartrees) and in kJ/mol.

Orbital Energies

    Orbital energies from ab initio and density functional calculations are given in atomic units (hartrees).

    Orbital energies from semi-empirical calculations are given in electron volts (eV).

Energy Conversions

hartrees kcal/mol kJ/mol eV cm-1
1 hartree 1 6.275 (2) 2.625 (3) 2.721 (1) 2.195 (5)
1 kcal/mol 1.593 (-3) 1 4.184 4.337 (-2) 3.498 (2)
1 kJ/mol 3.809 (-4) 2.390 (-1) 1 1.084 (-2) 8.359 (1)
1 eV 3.675 (-2) 2.306 (1)) 9.224 (1) 1 8.066 (3)
1 cm-1 4.556 (-6) 2.859 (-3) 1.196 (-2) 1.240 (-4) 1

Electron Densities, Spin Densities, Dipole Moments, Charges and Electrostatic Potentials

    Electron densities and spin densities are given in electrons/(atomic units)3.

    Dipole moments are given in debyes.

    Atomic charges are given in electrons.

    Electrostatic potentials are given in kcal/mol.

Vibrational Frequencies

    Vibrational frequencies are given in wavenumbers (cm-1).


Questions, comments, or suggestions?
webmaster@wavefun.com

Copyright 1995-98 Wavefunction, Inc. All rights reserved