Effective Interaction Energies for Weakly Bound Dimers at Room Temperature: (H2O)2, (N2O)2, (CO2)2, and (HCHO)2

Effective dimer bond energies at room temperature are experimentally determined by pressure broadening for rotational lines. Toward the understanding of the bond energies, thermal energies associated to the dissociation are theoretically evaluated by considering effective degrees of freedom.