which is the theory level that is commonly used in Gaussian to obtain the HOMO and LUMO energies of a molecule?
2006-08-15 14:28:45 · 3 answers · asked by lobis3 5 in Science & Mathematics ➔ Chemistry
The basis set was probably STO-3G, unless someone changed the default basis set.
The theory level used to actually calculate the HOMO and LUMO was probably AM1 or PM3. Although that is like buying a Porsche and putting crappy 87 octane gas in it.
Yes, I'm serious.
2006-08-15 17:29:17 · answer #1 · answered by Anonymous · 0⤊ 1⤋
You can obtain MO's with HF, or any DFT functional (like LSDA, OLYP, B3LYP, etc.), or just about any other method available, and with any basis set. The level of theory you use is not dictated by what you want to calculate, but rather by the accuracy with which you need to calculate it.
In other words, no what level of theory you use, you are still attempting to solve the same problem (i.e., the time-independent Schrodinger equation), you are just using a different set of approximations and methods to arrive at that solution.
2006-08-16 00:42:19 · answer #2 · answered by Anonymous · 1⤊ 0⤋
Holy balls!! Why would you ask that here?
2006-08-15 23:21:59 · answer #3 · answered by iandanielx 3 · 0⤊ 1⤋