The velocity of gadolinium atomic beam produced by electron-beam heating was derived from spectrum profiles measured by Doppler-Limited absorption. This method was free from a systematic error of laser beam incident angle because the collimated atomic beam was crossed perpendicularly with laser beams. The atomic velocity was 900 m/s at the deposition rate 30Å/s which was faster than the maximum velocity on the assumption of adiabatic free expansion under estimated evaporation surface temperatures. The excess of kinetic energy indicated a collision induced energy conversion between the atoms excited by electron bombardment.
