Temperature dependence of the apparent spin-spin relaxation times, T 2* measured with a super-regenerative oscillator on 35Cl containing molecules

Abstract

The temperature dependence of the resonance frequencies v and apparent spin-spin relaxation times T 2★ is reported for SbCl 3, CrCl 3 , GaCl 3, HgCl 2, p-φCl 2, KCl 3, and NaClO 3, using two proven techniques and a Dean type super-regenerative oscillator. The line shapes of the lines are not directly measured, T 2★, the inverse Line width parameter being obtained, (a) by measuring the quench frequency, T 1....T n at a fixed signal voltage output V o as a function of sample mass m 1....m n and using ▪ under specific operating conditions, or (b) by measuring the voltage change V 1....V n at a fixed sample mass m as a function of the quench frequency change, t 1....T n , using ▪ T 2* from (a) or (b) are self consistent. The equations apply only to pure Gaussian or Lorentzian line shapes. Lines are rarely pure Gaussian or Lorentzian, but consideration of the factors contributing to line shape shows the shape to be Gaussian. T 2★ values calculated assuming a Gaussian line shape for HgCl 2 , NaClO 3, CrCl 3, SbCl 3 , Cu 2O and p-φCl 2Cl 2 at room temperature, reproduce literature results. In GaCl 3 a phase transition is observed in the v dependence near 100° K for two of the three 35Cl lines, and the 71Ga and 79Ga lines. In CrCl 3 a new line is found, and its frequency and T 2★ measured. The T 2★ behaviour of p-φCl 2 as a function of sample preparation supports the idea that crystal memory is reflected in T 2★ but not in the frequencies v.