NONUNIVERSALITY IN SHORT-TIME CRITICAL-DYNAMICS

We study the behaviour of dynamical critical exponents of the two-dime nsional Ising model with a line of defects. Simulations done at an ear ly time (first 100 Monte Carlo steps) reveal that the critical exponen t theta of Janssen er al (Z. Phys. B 73 539) depends on the strength o f the exchange coupling constant (J') of the altered line. On the othe r hand, our simulations permit us to conclude that the dynamical criti cal exponent z is not sensitive to changes in J'. In addition, we inve stigate the possible invariance of the anomalous dimension (x(0)) of t he magnetization at the beginning of the process.