Techniques are described which utilize the "print out effect" to obtain both the direction and velocity of photoelectrons in silver chloride crystals in an electric field. Hall mobility of the electrons is calculated from their change in direction produced by crossed electric and magnetic fields. Drift mobility of the electrons is obtained by measurement of their velocity in known electric fields. The value obtained for the Hall mobility ($R\sigma$) multiplied by $\frac{8}{3\pi }$ is 51 ${\mathrm{cm}}^2$/volt sec at 25°C. The values obtained for the drift mobility are shown to be a function of temperature. A value of 49.5 ${\mathrm{cm}}^2$/volt sec was obtained at 25°C, which is within experimental error of $\left(\frac{8}{3\pi }\right)R\sigma$, indicating that acoustical scattering is the principal mechanism and that temporary trapping is unimportant. A summary of the behavior of conduction electrons in silver chloride, calculated from the results of these experiments, is included.

• Received 20 February 1951

DOI:https://doi.org/10.1103/PhysRev.82.935