ON THE RANDOM TRANSVERSE FIELD MIXED SPIN ISING-MODEL OF SPIN-1 2 ANDSPIN-1/

The critical behavior of mixed spin Ising model is investigated when t he transverse fields are randomly distributed. The calculation shows t hat when the transverse fields are both bimodally distributed, the tra nsition temperature decreases with increasing transverse field and eve ntually vanishes at a finite field. When one of the transverse fields is bimodally and the other trimodally distributed, the temperature dec reases but does not vanish. When both transverse fields are trimodally distributed, the transverse field dependence of temperature breaks of f and a tricritical point appears due to the interaction between quant um fluctuations and disorder.