Calculating Mulliken Charges

If you already have an optimized calculation done, chances are that you had ESP charges displayed in the .out file. (That's because you probably have the keyword icfit=1 in your .in file.)

To get Mulliken charges instead, what you do after your calculation is complete.
1. Copy the .01.in file to a new input file. You will then make the following changes to the &gen section of your new input file (call it filename_mulk.in or something like that, I use "mulk" to refer to Mulliken charges)
2. Remove the keyword igeopt=1 (since you don't need to optimize the geometry further, and it would take a l-o-n-g time if you did)
3. Add the keyword igonly=1 (since you don't need to converge the wavefunction again).
4. Add the keyword mulken=1
5. I usually remove ip11=2 and icfit=1 and any other "output" related keywords so the output file won't be so big and unwieldy.