1

Is there an equation, similar to the Rydberg formula, for calculating the energies of molecular orbitals?

For example, with the Rydberg formula, I can work out that the energy of a $1s$ orbital in hydrogen is $-13.6\ \mathrm{eV}$. Is there any way that I can calculate (or approximate) the energies of the bonding and anti-bonding orbitals in $\ce{H2}$?

Todd Minehardt
  • 10,556
  • 25
  • 52
  • 63
user1150512
  • 247
  • 1
  • 2
  • 6
  • 1
    It doesn't exist. Hydrogen atom can be solved exactly, multielectron systems can't. – Ivan Neretin Nov 18 '16 at 14:10
  • Ok, thanks! I believe multi electron systems can be approximated by calculating Zeff (for example with Slater's rules) - are there any things like this for the MOs? – user1150512 Nov 18 '16 at 14:13
  • 1
    Well, for conjugated systems you can use the Hückel method for getting relative energies, but that's about it. Since this was tagged as computational chemistry: it's very easy to use computational chemistry to predict MO energies. – DSVA Nov 18 '16 at 14:26
  • How would you go about doing it computationally? Are there any free software packages which are able to do it? Thank you. – user1150512 Nov 18 '16 at 14:37
  • 1
    I recommend Psi4. You can use Avogadro to help write input files and look at results. – pentavalentcarbon Nov 19 '16 at 16:53
  • For future googlers, the Avogadro link is broken, but https://avogadro.cc/ will get you there just fine. – cincodenada Jun 16 '22 at 05:12

0 Answers0