# Calculating excited states using GAMESS CISD module

I am trying to compare the energies of the excited states of $$\ce{C12H9N}$$ molecule using the CIS and CISD module implemented in the quantum chemistry package in GAMESS.

While I can easily obtain the results with the CIS module, the implementation of CISD module seems difficult and my program crashes every time. It will be really helpful if anyone can let me how to calculate the excited states with singles and doubles excitation.

An example would really help.

• Welcome to the site! I don't know much about GAMESS but it will likely help other users if you include the input file you are trying to run and, if small enough, the output or at least any error messages you are getting. – Tyberius May 10 at 12:57
• Yes, please include the input file and the error messages. I am only guessing, but it's possible that you don't have enough memory—the program will crash in that case. – Shoubhik R Maiti May 10 at 17:24
• +1. Welcome to the site and thank you so much for contributing your question here! We hope to see much more of you in the future !!! Can you please post your input file and output file? We can't say why the program is crashing if we don't see the error message. If the output file is a few thousand lines, please just put it in a code block, and if it's too long then put it in a folder called 4958 here since that's the number in this question's URL. – Nike Dattani May 11 at 3:10
• Sorry if you felt discouraged on the answer that you wrote. I think what people are saying is that if you were able to "figure out the problem and solve it" like your answer says, then it's very much appreciated if you write your solution here so that future users can benefit from it (as a bonus you'll also earn a lot more rep and this will allow you to participate more). Since you have a new problem, please ask that as a separate question if you didn't already ask it elsewhere! – Nike Dattani May 20 at 22:36
• @NikeDattani they have asked the new question with their other account mattermodeling.stackexchange.com/questions/4979/… – Tyberius May 23 at 0:45