DanSandberg said:
Excuse me for mis-typing then. The Roothan-Hall equations are merely a representation of the HF method, which is an approximation for the determination of the ground-state energy. I didn't realize you needed me to state all that information before asking my actual question. For the record, yes I am familiar with HF theory both RHF and UHF.
Good! As you noticed, I didn't get that impression from your original post. The impression I got was that you were trying to jump from the Schrödinger equation straight to semi-empirical methodology without first having a solid grasp of the intermediate levels of theory. But to me, a thorough understanding of HF theory does include knowing how it's implemented, which means knowing how the two-electron integrals are evaluated in practice. (And yes, I also know that the Roothan-Hall equations and HF method are the same thing. I don't get offended being told that they are, either.)
No offense but if you do not know the answer than why did you bother responding? Just because you don't feel compelled to know the answer doesn't mean it is irrelevant as it is applicable to a question stemming from my current academic pursuits.
I bothered responding because I suspected you might be wasting your time, either learning the details of methods you would likely never use, or attempting to implement these methods without first understanding the ones they build on. The only reasons I can see for knowing this, and asking how integrals are evaluated, is because you're interested in either implementing these methods or developing them further. Telling people they have to learn to walk before they can run
is being helpful, even if it appears to have injured your pride.
I could not (and still can't) understand what set of circumstances there'd be where someone would know how to calculate the Hartree-Fock two-electron integrals but have problems understanding the simplified ones used by the semi-empirical methods. Also, if method implementation/development was your interest, you'd know or wouldn't have any problems finding out, because you'd have a basic textbook on quantum chemistry. For instance, it's in section 3.9 of Jensen's "Introduction to Computational Chemistry", sec 16.5 of Levine's "Quantum Chemistry", sec 9.5 of Mueller's "Fundamentals of Quantum Chemistry".
Whereas if your interests were in just doing calculations, I'd suggest you learn about more modern semi-empirical methods such as PM3 or AM1.
Furthermore if you took the time to punch MNDO into google scholar, limiting search results to papers published after 2000, you will see these methods are QUITE relevant still and are frequently reparametrized.
A parametrization makes it a different method. (e.g. PM3 and AM1) Stock MNDO isn't used for calculations anymore. Nor could you (in most contexts) publish a paper having done straight-up Hartree-Fock calculations either. That doesn't mean dozens of papers aren't still being published that have something to do with Hartree-Fock. The fact that a method is obsolete for doing calculations doesn't make it obsolete from the method-development point of view. For reasons stated, I assumed you were interested in practical calculations, not method development.
I don't know what your intentions were in responding to my question but to be honest I found your response arrogant, dismissive and unhelpful. If you don't know the answer than move on. Do not tell me the question is not worth asking.
Sorry if you feel that way, but hey - you get what you paid for.
