Fourier Transform Spectroscopy and IR Spectroscopy

These flashcards cover key terms and concepts related to Fourier Transform Spectroscopy and Infrared Spectroscopy.

Fourier Transform

A mathematical conversion used to transform spectra from the time domain to the frequency domain.

Dispersive Instruments

Instruments that use a grating to separate wavelengths and acquire spectra one wavelength at a time.

IR Active Transitions

Molecular transitions that involve a change in dipole moment and thus absorb IR radiation.

Normal Modes of Vibration

Well-defined vibrations of atoms within a molecule characterized by degrees of freedom determined by molecular structure.

Selection Rules for IR Spectroscopy

For a vibrational mode to be IR active, there must be a change in dipole moment; for Raman activity, a change in polarizability must occur.

Molecular Vibrations

The motions of atoms in a molecule, which can be classified into stretching and bending modes.

FTIR

Fourier Transform Infrared Spectroscopy, a modern technique using Fourier transform methods to acquire IR spectra.

Raman Spectroscopy

A technique that studies vibrational transitions by observing the scattering of radiation from a molecule.

Michelson Interferometer

A device used in FTIR instruments to generate interference patterns for obtaining IR spectra.

Signal to Noise Ratio (S/N)

A measurement of the signal intensity relative to background noise; improved by averaging multiple scans.