Ultrafast lattice vibrational relaxation of optically excited F-centers in RbCl at 4.2 K

Employing a picosecond one-color pump-probe method, we have measured the lattice vibrational relaxation time of the electronically excited F-centers in RbCl. The lattice vibrational relaxation time is less than 3 ps and dependent on the excitation wavelength, slower at a shorter excitation wavelength.