MacResearch

A better question is not "how do I learn Gaussian," but rather "how do I learn computational chemistry techniques?" regardless of the program you use. After all, there are dozens of programs. Gaussian just happens to be the Microsoft Word of computational chemistry -- everyone assumes you use it.

There are a variety of good guides on the web and in print. I really like Essentials of Computational Chemistry by Cramer and Truhlar, or Introduction to Computational Chemistry by Jensen. On the web, you can search for "computational chemistry" or start with tutorials like CCL.net http://ccl.net/cca/documents/dyoung/topics-framed/

Let me answer your other points.

I'm not quite sure what you mean by "not all of the parameters are what I want." Could you be more specific? What are you trying to study?

And as for reading output files? There's a lot there, particularly depending on the level of output you requested. The key thing, IMHO is to realize that it's there if you need specific data. Otherwise, read the output file into GaussView or Avogadro or another visualization program. You can then display orbitals, vibrations, etc.

Always, the key question in research or asking on forums, is "what are you trying to accomplish?"

I suppose this is where the truth comes out, eh?

I'm in organic 2 right now, and I'm not having a lot of fun doing synthesis. I think I'd like to do some computational stuff in the future. All things considered, I'd like to start now, even though a lot of it is certainly over my head. The math is pretty hairy and I don't understand most of it. I just find it interesting, and I wasn't sure where else to start other than dive into some menial research work. If there are any other suggestions as to what to do on this front, they are greatly appreciated.

What we want to do is to study whether NMR analysis of hydroquinone and hydroquinidine are feasible in the sense of lowering the temperature to freeze their conformations. I have another article looking at the similar 4-methoxypyridine, specifically the barrier energy of the methoxy group. First, I'd like to replicate the results given in the paper. In GaussView I couldn't find the same basis sets, though I understand they may have to be entered manually. I'm probably over my head, but I find it so interesting. What to do...

look up qst2 on the gaussian website under keyword opt

Thank you very much for your response. I've already tried the methods TS, QST2 and QST3. My latest route section is:
opt=(calcall,qst2,maxcycle=50) ub3lyp/6-31g(d) int=grid=ultrafine
but this quits after the warnings:
Warning -- assumption of classical behavior for rotation
may cause significant error
[.........]
Warning -- explicit consideration of 13 degrees of freedom as
vibrations may cause significant error
[.........]
Error termination request processed by link 9999.
Error termination via Lnk1e......

In my input I'm using the DQH+ optimized molecule as the reactant, and the same molecule with a big bond length between DQ and H+, as the products.

I've also tried using the keywords opt=tight and freq=hindrot, but it seams that the last one causes greater problems.

Thank you again for your reply. I hope this message gives you more insight into what I'm dealing with.

I am also a research student who never used Gaussian or have any background in computational chemistry. I am attempting to determine the minimal energy confirmation of multiple molecules in relationship to one another. Does anyone have any suggestion on how to achieve this using Gaussian?
Thank you.