Ionization Energy Calculator


Directions :

This script calculates the ionization eneregy of your atom. It also compares the Subtraction method to the Koopmans' Method. In the Input section, you will enter the ion energy value, neutral atom energy value, HOMO energy value for the neutral atom, and the literature ionization energy value. The script then calculates your ionization values in three different units, hartrees, electron volts, and kiloJoules per mole. Finally, using the absolute values, the script calculates the percent error in each method. The absolute value is used because literature values are given in positive figures. Remember +/- represents whether the energy is being consumed or released. Here we are only concerned with the amount of energy not whether it is positive or negative.

Input Value(s):

Subtraction Method

Koopmans' Method

Energy value for Ion in Hartrees
Energy value for Neutral Atom in Hartrees
HOMO Value
Literature Ionization Energy Value (kJ/mol)

Ionization Energy in:

UnitsSubtraction MethodKoopmans' Method
Hartrees
Electron Volts (eV)
kiloJoules per Mole (kJ/mol)

Percent Errors:

Subtraction Method
Koopmans' Method


Developed by
Shodor logoThe Shodor Education Foundation, Inc.
in cooperation with the
National Center for Supercomputing Applications

© Copyright 1999-2000 The Shodor Education Foundation, Inc.