Brillouin scattering in diamond

Abstract

The Brillouin spectrum of diamond excited with either the Ar+ or .He-Ne laser radiation is measured with a triple-passed piezoelectrically scanned Fabry-Perot interferometer. The polarization features and the selection rules have been verified for a number of scattering geometries, From the measured frequency shifts of the Brillouin components, the following values are obtained for the elastic moduli: c && = 10.764~0.002 ' c i2 --1.252 + 0.023, and c 44 --5.774 + 0.014 in units of 10" dyn/cm'. The relative intensities of the observed Brillouin components for a variety of scattering geometries are consistent with the following elasto-optic contants: p 44 ---0.172 and p»-p» ---0.292 determined by Denning et al. and p» + 2p~2 = 0.1640 obtained by Schneider, From a comparison of the Brillouin spectrum and the Raman sp:ctrum associated with the zone-center optical phonon, observed under identical conditions, we obtaIin a value for the single independent component characterizing the Raman tensor per unit cell, viz. ,~a~= 4.4~0.3 A'.

Equation of state and phonon frequency calculations of diamond at high pressures

“…8,9,10,11,12 The analysis of diffraction data is usually based on adopting B ′ 0 = 4.0 obtained from ultrasonic measurements up to 0.2 GPa. 8 The only exception is the recent diffraction study of diamond to 140 GPa by Occelli et al, 7 who report B ′ 0 = 3.0, at variance with the ultrasonic measurement.…”

Равновесные Структуры Из Углеродных Алмазоподобных Кластеров И Их Упругие Свойства

“…1 и 4, в табл. 5 приводятся экспериментальные данные для кубического алмаза из работ [59][60][61][62]. Из сравне-ния можно видеть, что объемный модуль кубического алмаза (∼ 440 GPa) превосходит объемные модули всех рассмотренных алмазоподобных фаз.…”

Моделирование Перехода Графита В Алмаз В Изэнтропическом Процессе

“…Параметры алмаза определялись в эксперименталь-ных [34][35][36][37][38][39][40][41] и теоретических [42][43][44][45][46][47] работах. Для ал-маза приняты следующие значения: V 0 = 3.417 cm 3 /mol (ρ 0 = 3.5155 g/cm 3 ), E 0 = 1.82 · 10 3 J/mol относительно графита, B S,0 = 4.46 Mbar, q 0 = 4.0, D,0 = 1874 K и Ŵ D,0 = 1.0.…”