Abstract
We report a three-pulse, pump-probe experiment on and local modes in and using the Dutch free electron laser, FELIX. The 10-K lifetimes of the local modes were measured as and for and respectively. For the corresponding 10-K lifetimes are and Three-phonon anharmonic decay accounts for the temperature dependence of the lifetimes, while two-phonon anharmonic decay is expected to apply for the lifetimes. However, the in lifetime is anomalous in requiring the three-phonon decay occasioned by a close resonance of this mode with a three-phonon lattice peak. From a combination of lifetime and linewidth measurements, the pure dephasing rates of these hydrogenic local modes have been determined and well accounted for by elastic band-phonon scattering processes.
- Received 21 May 2001
DOI:https://doi.org/10.1103/PhysRevB.64.144303
©2001 American Physical Society