Ionization Energy Main Page
First year chemistry curriculum concepts
Second year chemistry curriculum concepts
Glossary of Terms
Quick Guide to DISCO Output File
SUCCEED's Computational Chemistry
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Part I: Ionization of a Metal
- Create a spreadsheet that you can use to do your calculations. Title the
first column 'Charge', the second column 'Ionization Energy', and the third
column 'HOMO Energy'. In the 'charge' column list the numbers 0 through +3.
- Next, select a metal element of your choice. Representative elements (not
transition elements) work best. Be sure to pick an element that has a basis
- Using the Waltz Interface for DISCO, create a run for the neutral atom of
the metal you chose. First, enter a '1' into the periodic table under your
element. (We are only looking at single atoms and ions, not molecules.) Also
make sure that the calculation options are set to the defaults and 'Electron
Density' is selected. Click continue.
- For the neutral atom, the charge should equal zero. You may select the
basis set of your choice. Consistency in basis sets is a suggestion.
- When you have chosen your basis set, select 'DO DISCO'.
- Waltz will then produce images of the atom or ion and create output files.
- Open the 'Energy file' and copy the given value into your spreadsheet.
- Also open the output file. Under the information for the iterations is a
section called 'Eigenvectors and Orbital Energy'. Locate the HOMO and copy the
HOMO energy value into your spreadsheet.
- Repeat steps 3-7 for the first three ions of your element. Note that each
ion has a different charge. When you prepare your run, remember to change the
'charge' box to +1, +2, or +3.
- The energy values that you receive are given in hartrees
(Eh. You will want to use your spreadsheet to convert these values
into electron volts (eV). There are 27.216 eV/Eh.
- Finally, graph the charge on the element against the ionization
energy. Find the atom or ion with the minimum energy value. Observe how the
energy changes as electrons are lost.
Part II: Ionization of a Non-Metal
Choose a non-metal and repeat Part I using a neutral atom, -1, -2, and -3
Part III: Subtraction vs. Koopman's Theory
For this section you will need your spreadsheet information, the ionization
calculator, and your ionization energy literature values.
- Open a new spreadsheet. Create three columns. Title the first column
'Ion', the second 'Subtraction Method' and the third 'Koopman's Theory'. Under
the first column list your three ions.
- Using the ionization calculator, fill in the values you recorded for the
energy value of the ion, neutral atom, and HOMO energy as given in
Hartrees. (The calculator automatically converts hartrees to eV and kJ/mol.
- Next, enter your literature value for the correct ionization as given in
kJ/mol and click 'Evaluate'.
- The calculator should give you your converted units for both method. It
also displays the percent errors for each method compared to the literature
values. Record each of the two values in the appropriate column in your
- Repeat steps 2-4 for each of your ions.
- Graph the ions vs. each of the two methods and determine which method is
- Repeat this section for your non-metal element.