Infra-red spectroscopy of molecules was introduced 110 years ago by Coblentz[cite]10.1103/PhysRevSeriesI.20.273[/cite] as the first
functional group
spectroscopic method (“
The structure of the compound has a great influence on the absorption spectra.
References
Physical and Theoretical ChemistryGeneral Physics and Astronomy
Autori Ming Wah Wong, Kenneth B. Wiberg, Michael Frisch
A compact formalism for the second and third derivatives of the Hartree–Fock energy in the presence of an Onsager solvent reaction field is presented. All three standard algorithms (MO, AO, and direct) are extended to include the reaction field in a unified way. Predictions of the infrared spectrum of formaldehyde in a variety of solvents and of solvent-induced shifts in carbonyl stretching frequencies are presented along with the results of new measurements. As for the gas-phase case, analytical second derivatives are far more efficient than numerical ones. The reaction field provides very good predictions of solvent effects at negligible computational cost.