Аннотация:Studies are reported of the expansion into vacuum of a cloud of dense vapor produced by the action of a nanosecond laser pulse on the surface of a solid body. The investigation is based on the well-known particular solution of the gasdynamic equations describing the expansion into vacuum of a gas cloud in the shape of a triaxial ellipsoid. The analysis presented here provides an explanation for the" flipover" effect observed in a deposited spot. It is shown that the solution thus constructed can be used to interpret the results of time-of-flight mass spectroscopy and to describe the shape of a vapor cloud expanding into a medium with an ambient pressure. The rate of flow of vapor onto a planar substrate and the transverse profile of the film that forms as a result of vapor condensation on the substrate are calculated. The dependence of this profile on the shape of the focal spot is determined. A simple analytical expression is found for the transverse profile in the range of parameters typical of the laser technique for obtaining thin films. O I995 American Institute of Physics.