Abstract

From the measurements of the intensities of thermal diffuse scattering observed in the stationary-crystal photographs taken with monochromatic Cu K radiation, all the nine elastic constants of orthorhombic 1,3,5-triphenylbenzene single crystals have been determined by the photographic method. Each constant is evaluated from two or more directions of thermal wave vectors. The reciprocal nodes involved for the determination of all the constants were 200, 206, 002, 015 and 006. Diffusely scattered intensities were corrected for general scattering, polarization and skew factors. Corrections for absorption, divergence and second-order diffuse scattering were found negligible. The values of elastic constants in units of 1010 dynes.cm-2 are C11 = 0.31, C22 = 1.36, C33 = 2.33, C44 = 5.02, C55 =0.34, C66 = 3.69, C12 = -1.78, C13 = 0.92 and C23 = 0.80. Correlation of the elastic data with the structure have been attempted.