Picosecond temperature and pressure jumps in ice

A sensitive picosecond thermometer and manometer for hydrogen-bonded systems is demonstrated. The technique is applied for temperature jumps in ice by the help of subpicosecond pulses in the mid-infrared. The hydroxilic stretching vibrations ( OH or OD) are applied for energy deposition and for the fast and sensitive spectral probing of local structure and thermodynamic condition. The method is verified in isotopically mixed ice at 200 K and ambient pressure. The transient data show that the local quasi-equilibrium in ice builds up within 25 ps allowing definition of a local temperature. Measurements performed close to the melting point provide no evidence for melting after energy deposition, but for substantial superheating of the ice lattice to 300 K that persists over the monitored time interval of 1.3 ns.