Spectroscopy

(noun)

use of light, sound or particle emission to study matter. The emissions provide information about the properties of the matter under investigation. The device often used for such analysis is a spectrometer, which records the spectrum of light emitted (or absorbed) by a given material.

Related Terms

Examples of Spectroscopy in the following topics:

  • The Spectrometer

    • This type of instrument is used in spectroscopy.
    • Spectroscopy studies the interaction between matter and radiated energy.
    • When the spectrometer produces a reading, the observer can then use spectroscopy to identify the atoms and therefore molecules that make up that object.

  • Structural Determination

    • Structural determination using isotopes is often performed using nuclear magnetic resonance spectroscopy and mass spectrometry.
    • Structural determination utilizing isotopes is often performed using two analytical techniques: nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS).
    • Mass spectrometry and nuclear magnetic resonance detect the difference in an isotope's mass, while infrared spectroscopy detects the difference in the isotope's vibrational modes.

  • Carbon NMR Spectroscopy

    • The power and usefulness of 1H nmr spectroscopy as a tool for structural analysis should be evident from the past discussion.
    • The most important operational technique that has led to successful and routine 13C nmr spectroscopy is the use of high-field pulse technology coupled with broad-band heteronuclear decoupling of all protons.
    • Unlike proton nmr spectroscopy, the relative strength of carbon nmr signals are not normally proportional to the number of atoms generating each one.

  • Vibrational Spectroscopy

  • Carboxylic Acids

    • Carboxylic acids can be characterized by IR spectroscopy; they exhibit a sharp band associated with vibration of the C-O bond between 1680 and 1725 cm-1.
    • By 1H NMR spectroscopy, the hydroxyl hydrogen appears in the 10–13 ppm region, although it is often either broadened or not observed owing to exchange with traces of water.

  • Introduction

    • Over the past fifty years nuclear magnetic resonance spectroscopy, commonly referred to as nmr, has become the preeminent technique for determining the structure of organic compounds.
    • Although larger amounts of sample are needed than for mass spectroscopy, nmr is non-destructive, and with modern instruments good data may be obtained from samples weighing less than a milligram.
    • Strong magnetic fields are necessary for nmr spectroscopy.
    • Nmr spectroscopy is therefore the energetically mildest probe used to examine the structure of molecules.

  • Detection and Observation of Radicals

    • Just as a proton (spin = 1/2) will occupy one of two energy states in a strong external magnetic field, giving rise to nmr spectroscopy; an electron (spin = 1/2) may also assume two energy states in an external field.
    • This complexity is the result of hyperfine splitting of the resonance signal by protons and other nuclear spins, an interaction similar to spin-spin splitting in nmr spectroscopy.

  • Emission Spectrum of the Hydrogen Atom

    • Each element's emission spectrum is unique, and therefore spectroscopy can be used to identify elements present in matter of unknown composition.
    • Further series for hydrogen as well as other elements were discovered as spectroscopy techniques developed.

  • UV-Visible Absorption Spectra

    • Consequently, absorption spectroscopy carried out in this region is sometimes called "electronic spectroscopy".
    • The presence of chromophores in a molecule is best documented by UV-Visible spectroscopy, but the failure of most instruments to provide absorption data for wavelengths below 200 nm makes the detection of isolated chromophores problematic.

  • Proton NMR Spectroscopy