Before revision:  it is shown that the perturbation of the fluorescence spectra of embedded molecules to the pressure impulses is determined by the thermodynamic state of the interface , or in other words, the thermodynamic susceptibilities such as the compressibility or heat capacity of the system.
After revision:  it is shown that the perturbation of the fluorescence spectra of embedded molecules to the pressure impulses is determined by the thermodynamic state of the interface . We derive the coupling between the energy fluctuations of a fluorophore and its environment allowing the thermodynamic susceptibility, in particular, the system.