Gas-phase calorimetry of protonated water clusters

Protonated water clusters with 60 to 79 molecules have been studied by nanocalorimetry. The technique is based on multi-collision excitations of the accelerated clusters with helium. The caloric curves indicate transitions that resemble those of water clusters charged by an excess electron, but the transition temperatures of the protonated clusters are higher. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4705266]