Calculations of the Al phonon frequency in photoexcited tellurium are prese
nted. The phonon frequency as a function of photoexcited carrier density an
d phonon amplitude is determined. Recent pump-probe experiments are interpr
eted in light of these calculations. It is proposed that, in conjunction wi
th measurements of the phonon period in ultrafast pump-probe reflectivity e
xperiments, the calculated frequency shifts can be used to infer the evolut
ion of the density of photoexcited carriers on a subpicosecond time scale.
[S0031-9007(99)09219-4].