Dear all, I am performing some tests using spinmc (alps 2.0, Heisenberg model) on uncoupled spins changing the number and magnitude of spins at different fields. There are some things in the results that I dont understand: The energy is always zero, independently of the magnitude of the field for the uncoupled case, if I put a coupling constant, then I get as expected a non-zero value for the energy, but it is still non-dependent on field as it should be because of the Zeeman term. In a previous post, it is said that the susceptibility is calculated from magnetization^2, so it should work while M is linear on H, is there a way to get the dependence of susceptibility against field as the system approaches to saturation? And regarding the direction of field, setting H=1 means: Hz=1 Hx, Hy and Hz=1 Hx^2+Hy^2+Hz^2=1^2 , Hx=Hy=Hz or something else? I also tried to set H="0 0 1" and the program runs, but i dont know what I am actually getting. Any comments are welcome Kind Regards Daniel