Accession Number : AD0614809

Title :   N.M.R. STUDIES OF SOLIDIFIED H2 - D2 MIXTURES, I. STEADY-STATE EXPERIMENTS,

Corporate Author : OHIO STATE UNIV RESEARCH FOUNDATION COLUMBUS

Personal Author(s) : Gaines,J. R. ; de Castro,E. M. ; Daunt,J. G.

Report Date : APR 1965

Pagination or Media Count : 48

Abstract : Steady state NMR measurements using a marginal oscillator technique at 10 Mc/sec were made on solid mixtures of nH2 - nD2 of nH2 concentration from 100% to 1% in the temperature range 1.1K to about 12K. Striking differences in the line shape were observed, particularly in the n-D2 rich sample, with change in temperature, the line shape at the lowest temperatures revealing a composite structure. The question whether this line shape transition is due to isotopic phase separation is discussed and this interpretation is considered unlikely. It is concluded that the transition is probably associated with a hindering of the rotation of the orthoH2 molecule. Narrowing of the resonance lines with increasing r.f. power was observed. It is shown that no satisfactory explanation of this effect is possible using the Bloch equations. This narrowing is in excellent agreement with a recent calculation by Provotorov, however, and his theory is used to obtain a value of the exchange interaction in solid H2 of approximately 10 to the -7th power K. The progressive saturation technique is used to obtain values of the product (T-1)(T-2) for several of the mixtures. The data showed that (T-1)(T-2) has a value of 4.2K of about 0.000002 sq. sec for concentrations of nH2 from 10% to 100%. (Author)

Descriptors :   (*SOLIDIFIED GASES, NUCLEAR MAGNETIC RESONANCE), (*HYDROGEN, NUCLEAR MAGNETIC RESONANCE), (*DEUTERIUM, NUCLEAR MAGNETIC RESONANCE), (*NUCLEAR MAGNETIC RESONANCE, SOLIDIFIED GASES), RADIOFREQUENCY SPECTROSCOPY, LINE SPECTRA, TRANSFORMATIONS, MOLECULAR PROPERTIES, CRYOGENICS

Distribution Statement : APPROVED FOR PUBLIC RELEASE