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.