Radiation-driven rotational motion of nanoparticles

Focused synchrotron beams can influence a studied sample via heating, or radiation pressure effects due to intensity gradients. The high angular sensitivity of rotational X-ray tracking of crystalline particles via their Bragg reflections can detect extremely small forces such as those caused by field gradients. By tracking the rotational motion of single-crystal nanoparticles embedded in a viscous or viscoelastic medium, the effects of heating in a uniform gradient beam and radiation pressure in a Gaussian profile beam were observed. Changes in viscosity due to X-ray heating were measured for 42   µ m crystals in glycerol, and angular velocities of 10 − 6   rad   s − 1 due to torques of 10 − 24   N   m were measured for 340   nm crystals in a colloidal gel matrix. These results show the ability to quantify small forces using rotation motion of tracer particles.

Source: Journal of Synchrotron Radiation - April 25, 2018 Category: Physics Authors: Liang, M. Harder, R. Robinson, I. Tags: rotational X-ray tracking radiation pressure rotational dynamics research papers Source Type: research