Question

20. For which of the following molecules would the infrared active vibration modes be theoretically Raman inactive and the infrared inactive vibration modes be theoretically Raman active? (a) NH (b) (c) H Si... Η H B ΓΗ a H (d) Cl—c5c-ci (e) H

Please explain each choice. Also, explain what means "the least intense" in IR spectrum?

Answer 1

Mutual Exclusion Principle For molecules with a center of symmetry, no IR active transitions are Raman active and vice versa =>Symmetric molecules IR-active vibrations are not Raman-active. Raman-active vibrations are not IR-active. O=C=0 2=C=0 O=C=0 =c=0 Raman active IR inactive Raman inactive IR active Ka