Experimental relative intensities of fragments (H2O) n H+ (black lines) from the collision of (H2O)30H+ with H2O molecules at four center-of-mass collision energies E cm. Continuous and dashed red lines are obtained from Monte Carlo simulations (continuous line: 3n − 6 degrees of freedom, ν 0 = 5.5 THz, dashed line: 6n − 6 degrees of freedom, ν 0 = 6.5 THz, see text).
Experimental data points for −ln(I/I 0) (see relation (1)) as a function of the product of water vapor density in the cell times the cell length. The continuous line is a linear fit through the data points. The fit yields a value of 125 Å2 for the fragmentation cross section. The data points are obtained for (H2O)30H+ clusters at a collision energy of 2.3 eV.
Fragmentation cross section, relative to the geometrical cross section, plotted for various cluster sizes and collision energies. (a) Fragmentation of deuterated heavy water clusters induced by collisions with heavy water molecules. (b) Fragmentation of protonated water clusters induced by collisions with water molecules.
Cross section of the fragmentation of (H2O)30H+ induced by collisions with H2O molecules as a function of collision energy for two different initial temperatures of the cluster (25 K and 100 K). The continuous and dashed lines are obtained from a Monte Carlo simulation using the model described in the text. Continuous line: 3n − 6 degrees of freedom, ν 0 = 5.5 THz, dashed line: 6n − 6 degrees of freedom, ν 0 = 6.5 THz. The straight line (red online) at 210 Å2 is the geometrical cross section.
The radial energy transfer: only the energy transferred along the radial component v radial is assumed to be transferred into internal energy.
Fragmentation cross section, relative to the geometrical cross section, plotted as a function of the duration of the collisions for different cluster sizes for D2O (a) and H2O (b) clusters. The vertical lines indicate the vibrational period deduced here from ν 0 = 5.5 THz.
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