.

The details of this example can be found in the following article: (Z. Takáts, L. Drahos, G. Schlosser and K. Vékey, Is Formation of Hot Ions Feasible in Electrospray?, Anal. Chem. in press

Calculated (B3-LYP/6-31G(d,p)) vibrational frequencies (cm^-1) of p-methoxy-benyzlpyridinium ion: click here to download this MassKinetics frequency file.

Collisional cooling can be modeled reasonably well assuming long-lived collision complexes. In such a case the total energy of the two collision partners (the internal energy of the two partners and their relative rotational and translational energy) is distributed statistically between the various degrees of freedom. This process has been studied by MassKinetics model calculations. Preliminary results are shown in this figure illustrating the change of mean internal energy as a function of the number of collisions. Calculations were performed for p-methoxy-benyzlpyridinium ion colliding with Ar, N₂ and isobutane collision gases. The model calculations clearly show, that isobutane is the best cooling medium, and that the difference between Ar and N₂ is much less than that between N₂ and isobutane. The cooling rates shown here. agree very well with the experimentally observed difference between these curtain gases.

The corresponding MassKinetics project file will be available when MassKinetics Scientific version is released.