Electron-nucleus double resonance

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The electron nuclear double resonance ( English electron nuclear double resonance , ENDOR ) is a special form of ESR - spectroscopy .

Functionality and application

ENDOR spectroscopy combines the advantages of nuclear magnetic resonance spectroscopy (NMR spectroscopy, high resolution) and electron spin resonance (ESR, high sensitivity) by applying both forms of spectroscopy to one sample at the same time.

The ESR signal is used as an indicator for a suitable NMR, which can clearly better determine the number of signal lines around this point due to its high resolution. ENDOR spectroscopy uses the interactions of unpaired electrons ( paramagnetic impurities, free radicals or similar; sometimes also referred to as "paramagnetic electrons") with neighboring atomic nuclei. These are known under the name super hyperfine interaction .

Applications of ENDOR spectroscopy are biochemistry and organometallic chemistry (e.g. research into endohedral complexes ) as well as defects (impurities) in crystal lattices ( e.g. in semiconductors ) or chirality .

The technique was developed by George Feher in the mid-1950s . In 1957, he first investigated F centers in potassium chloride crystal lattices.

Variants of the process are pulsed ENDOR spectroscopy, optically detected ENDOR spectroscopy (ODENDOR, optically detected ENDOR) and ENDOR detected via a change in conductivity (EDENDOR, electrically detected ENDOR).

See also

literature

  • Johann-Martin Spaeth: Electron-nuclear double resonance investigation of U-centers in potassium chloride . In: Journal of Physics . tape 192 , 1966, pp. 107–141 ( ub.uni-paderborn.de [PDF; accessed on December 22, 2014]).

Individual evidence

  1. ↑ L. Dalton, H. Thomann et al .: Magnetic Properties II: ENDOR of Undoped CIS- (CH) x . In: Journal de Physique . Colloque C3, supplement to No. 6, No. 44 , 1983, pp. 229–232 ( hal.archives-ouvertes.fr [PDF; accessed December 22, 2014]).