Absorption Type 1H-{14N} Double Resonance Spectrometer

Abstract

An absorption (single-coil) type high resolution proton magnetic resonance spectrometer (JNM-3, 40 Mc/s) has been reconstructed into a double resonance spectrometer. The second r-f field at about the ¹⁴N resonance frequency is supplied with a variable frequency oscillator using a Clapp circuit. A double resonance probe houses two r-f coils and a glass Dewar tube (20 mm o.d.). The coil for ¹⁴N resonance is of Helmholtz type and is wound on the Dewar tube coaxially with the proton resonance coil. Nitrogen gas of the constant temperature is streamed around the sample tube, to avoid the temperature rise in the sample due to the large second r-f field supplied during the operation. The completely decoupled proton spectrum of formamide has been observed, in which the fine structure expected for the 40 Mc/s spectrum has been clearly resolved.