Electron diffraction studies of molecular clusters generated in supersonic flow

olecular clusters of ;Modifications of the electron diffraction apparatus were made to enable the measurement of cluster velocities by a time-of-flight technique. The dependence of velocities on flow conditions was studied. Clusters were found to lag behind the carrier gas by up to 14%. A procedure was developed to estimate cluster temperatures from observed lattice constants. This method uses a crystal's heat capacity and lattice constants measured at two or more temperatures to model the nonlinear variation of the unit cell volume with temperature. It successfully characterizes bulk Ar,...