Mallikarjunaiah K J, Jugeshwar Singh K, Ramesh K P, Damle R
Department of Physics, Bangalore University, Bangalore-560 056, India.
Magn Reson Chem. 2008 Feb;46(2):110-4. doi: 10.1002/mrc.2097.
(CH3)4NGeCl3 is prepared, characterized and studied using 1H NMR spin lattice relaxation time and second moment to understand the internal motions and quantum rotational tunneling. Proton second moment is measured at 7 MHz as function of temperature in the range 300-77 K and spin lattice relaxation time (T1) is measured at two Larmor frequencies, as a function of temperature in the range 270-17 K employing a homemade wide-line/pulsed NMR spectrometers. T1 data are analyzed in two temperature regions using relevant theoretical models. The relaxation in the higher temperatures (270-115 K) is attributed to the hindered reorientations of symmetric groups (CH3 and (CH3)4N). Broad asymmetric T1 minima observed below 115 K down to 17 K are attributed to quantum rotational tunneling of the inequivalent methyl groups.
制备、表征并研究了(CH3)4NGeCl3，使用1H NMR自旋晶格弛豫时间和二阶矩来理解其内部运动和量子旋转隧穿。在7 MHz下测量质子二阶矩，作为300 - 77 K温度范围内温度的函数，并且使用自制的宽线/脉冲NMR光谱仪在两个拉莫尔频率下测量自旋晶格弛豫时间(T1)，作为270 - 17 K温度范围内温度的函数。使用相关理论模型在两个温度区域分析T1数据。较高温度(270 - 115 K)下的弛豫归因于对称基团(CH3和(CH3)4N)的受阻重取向。在115 K以下直至17 K观察到的宽的不对称T1最小值归因于不等价甲基的量子旋转隧穿。
