Andrew E R, Kempka M
Department of Physics, University of Florida, Gainesville 32611, USA.
Solid State Nucl Magn Reson. 1995 May;4(4):249-53. doi: 10.1016/0926-2040(95)00003-9.
The temperature dependence of the proton nuclear magnetic resonance (NMR) relaxation time T1 and second moment M2 of polycrystalline beta-estradiol hemihydrate (1,3,5-estratriene-3,17 beta-diol) is measured at frequencies of 14 and 25 MHz. Below 260 K relaxation is found to be dominated by C3 reorientation of the single methyl group in each molecule, characterized by an activation energy of 9.4 +/- 0.1 kJ/mol. Above 260 K another relaxation mechanism becomes evident, characterized by an activation energy of 22 +/- 2 kJ/mol and ascribed to motion of the water molecules in the solid.
在14和25兆赫的频率下，测量了多晶型半水合β-雌二醇（1,3,5-雌甾三烯-3,17β-二醇）的质子核磁共振（NMR）弛豫时间T1和二阶矩M2的温度依赖性。在260K以下，发现弛豫主要由每个分子中单个甲基的C3重取向主导，其活化能为9.4±0.1kJ/mol。在260K以上，另一种弛豫机制变得明显，其活化能为22±2kJ/mol，归因于固体中水分子的运动。
