title: Persistent nuclear wave packet oscillation coexistent with incoherent vibrational population at excited F centers in KI.
abstract: We investigated nuclear wave packet dynamics in the excited state of KI F centers at 10 K using time-resolved luminescence spectroscopy. Observed transient spectrum is divided into oscillatory and non-oscillatory components. The former lasts over 11 ps without appreciable damping and is attributed to the oscillation of the wave packet consisting mainly of the A(1g) mode around the center. The non-oscillatory part rises quickly after photo-excitation exhibiting a cooling of incoherent vibrational population. This behavior suggests the fast energy dissipation due to the dephasing of the bulk phonon modes.
authors.affiliation: Institute for Solid State Physics, The University of Tokyo, Kashiwanoha 5-1-5, Kashiwa-shi, Chiba 277-8581, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Koyama
authors.forename: Youtarou
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Makoto
authors.initials: M
authors.lastname: Nakajima
authors.forename: Tohru
authors.initials: T
authors.lastname: Suemoto