C566lecture22_000

C566lecture22_000 - 1 C566 Master Lecture Notes Lecture 22...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 1 C566 Master Lecture Notes Lecture 22 Electronic and molecular structures of simple triatomics can frequently be predicted using Walsh diagrams. (from Herzberg polyatomics) The way to use these is to determine the number of electrons in valence orbitals, then chuck into the available energy levels and see if linear or bent gives lower energy. For BeH 2 (or BH 2 + ), there are 2 + 1 + 1 electrons, so this would be a linear molecule. Promotion of one of the u electrons into the LUMO actually results in a bending of the molecule. For BH 2 neutral with 5 electrons, the molecule is bent, but the first excited state is linear. CH 2 6 e , bent NH 2 7 electrons (bent) H 2 O 8 e bent Draw out why the u a 1 conversion is so stabilizing, while the b 1 is not. Why do the two lowest sigma bonds get destabilized? (repulsion) 2 From JPC This is a Walsh diagram tuned with the Huckel treatment of NO 2 . See page 352 of your text for a clearer picture of the AB 2 and HAB Walsh diagrams. Another common chromophore: simple double bond, * type transitions for Consider ethylene: C == C C == C H H H H y z 3 Highest symmetry axis is C 2 , but it has three C...
View Full Document

Page1 / 6

C566lecture22_000 - 1 C566 Master Lecture Notes Lecture 22...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online