| Ab initio molecular dynamics trajectories of two hydrogen-bonded cluster systems have been studied using time-dependent methods of vibrational analysis. The discussion in this manuscript is presented in two parts, each regarding one of the two cluster systems. The first contains hydroxy isoprene radical, an atmospheric reaction intermediate which feeds into numerous subsequent reactions affecting regional air quality and pollution.[1--6] Here, the effect of adsorption to a water cluster on the stability and vibrational properties are investigated and reported, identifying internal rotational-vibrational couplings at the adsorption site. The second system is the Zundel cation, H2O˙˙˙H+˙˙˙OH2. A doublet feature near 1000 cm-1 in the vibrational spectroscopy has previously been attributed to a peak splitting involving a shared proton transfer mode along with one or more of several other modes implicated in different reports in the literature.[7--13] Here, a coordinate invariant approach incorporating group symmetry projectors on time translation is used to extract the vibrational motion of the doublet feature without reference to or reliance on a choice zeroth order modes. Three publications result from the work represented in this manuscript.[14--16]... |
