[Tlaloc]

How do you construct an ion in Gaussian? I am using the visual interface Gaussview. Say, I have a neutral structure, how do I add or remove an electron? I found no reference in the manual about how to do this.

Thank you

[tamim83]

You need to do that in the input file.  You can do this manually or using Gaussview (it is part of those menus that helps you to set up your job).  If you do this manually, open your input file in a text editor.  The line before the molecular coordinates specifies the charge (first number) and the spin multiplicity (second number).  You'll need to change them both in most cases.  Beware of the spin multiplicity-it should be an odd number for even electron species and and an even number for odd electron species.