THE TEMPERATURE DEPENDENCE OF THE NUCLEAR QUADRUPOLE RESONANCE IN SOME MOLECULAR SOLIDS

Thesis/Dissertation · Mon Jan 01 04:00:00 EST 1962

OSTI ID:4669681

Richardson, C B

The nuclear quadrupole resonance of Cl and its Zeeman effect were observed in the following compounds over the range of temperature indicated: paradichlorobenzene, 195 c- K to 304 c- K; 1,2,3,4 tetrachlorobenzene, 78 c- K to 291 cand chloranil, 78 c- K to 374 c- K. The temperature dependence of the nuclear-quadrupole- resonance (nqr) frequencies and the field gradient asymmetries were used with the Bayer theory of the dependence to deduce the rigid body libration amplitudes in the latter 2 compounds. A structural change in chloranil at a temperature near 100 c- K was detected and carefully investigated by the nqr. The change appears to be an order-disorder transition. The evidence supporting this conclusion is presented and discussed at length. The nqr in dichloroethylene and molecular Cl was observed over a wide temperature range in an effort to detect free rotation.'' In the former, signal fadeout'' occurred about 100 c- C below the melting point, and did not appear at a higher temperature. In molecular Cl the signal was visible up to the melting point, indicating no disordering. An unexplained increase in signal strength, together with a decrease in the nqr temperature dependence, occurred about 6 c- below the melting point. A variable-temperature nqr Zeeman recording spectrometer, in which resonance is detected by slowly rotating a single crystal sample in a constant magnetic field, recording the relative amount of radiofrequency energy absorbed by the sample as a function of orientation, is described. (Dissertation Abstr.)

• Research Organization: Originating Research Org. not identified
• NSA Number: NSA-17-026249
• OSTI ID: 4669681
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ABSORPTION
BENZENE
CHLORINE
DETECTION
ENERGY
FREQUENCY
LATTICES
MAGNETIC FIELDS
MAYER THEORY
MELTING
MOLECULES
MONOCRYSTALS
NUCLEAR MAGNETIC RESONANCE
PHYSICS
QUADRUPOLES
RADIO WAVES
ROTATION
SIGNALS
SOLIDS
SPECTRA
SPECTROMETERS
TEMPERATURE
TRANSIENTS
ZEEMAN EFFECT