Acoustic phonons in chrysotile asbestos probed by high-resolution inelastic x-ray scattering

Acoustic phonons in an individual, oriented fiber of chrysotile asbestos (chemical formula Mg3Si2O5(OH)4) were observed at room temperature in the inelastic x-ray measurement with a very high (meV) resolution. The x-ray scattering vector was aligned along [1 0 0] direction of the reciprocal lattice, nearly parallel to the long axis of the fiber. The latter coincides with [1 0 0] direction of the direct lattice and the axes of the nano-channels. The data were analyzed using a damped harmonic oscillator model. Analysis of the phonon dispersion in the first Brillouin zone yielded the longitudinal sound velocity of (9200 ± 600) m//s.