Nuclear resonant scattering of Synchrotron radiation from nuclei in the Browninan motion

The time evolution of the coherent forward scattering of Synchrotron radiation for resonant nuclei in Brownian motion is studied . Apart from target thickness, the appearance of dynamical beats also depends on $\alpha$ which is the ratio of harmonic force constant to the damping force constant of a harmonic oscillator undergoing Brownian motion.