  TlCuCl3 shows a quantum phase transition from a spin-gap phase to a
Neel-ordered ground state as a function of magnetic field around H_{C0}~4.8T.
  From measurements of the specific heat c and the linear thermal expansion
alpha_i we calculate the Grueneisen parameter Gamma_i(T)=alpha_i/c. Close to
H_{C0} we find a diverging Gamma_i(T->0, in qualitative agreement with
theoretical predictions. However, the predicted individual temperature
dependencies of alpha(T) and c(T) are not reproduced by our experimental data.
