The study of acenaphthene and its complexation with water

Abstract

Acenaphthene (Ace) is a three ring polycyclic aromatic hydrocarbon (PAH), which consists of naphthalene and a non-aromatic five member ring. Ace has been previously been studied by microwave spectroscopy where the rotational constants were reported[1]. New measurements from 2-8 GHz using chirped pulse-Fourier transform microwave spectroscopy (CP-FTMW) will be presented. The high sensitivity achieved enabled us to observe all $^{13}$C isotopologues in natural abundance and determine the Kraitchman substitution structure. The spectra of Ace complexed with water and H$_{2}$$^{18}$O were also recorded at this frequency range. From these spectra, we have been able to assign the complexes Ace-(H$_{2}$O)$_{n}$, n=1-3 and (Ace)$_{2}$-H$_{2}$O and experimentally derive the O-atom position of the H$_{2}$O. The Ace-(H$_{2}$O)$_{3}$ complex is especially interesting as the water aggregate forms a slightly distorted cyclic water trimer from that observed in the IR[2]. These complexes could give insight about the formation of ice grains in the interstellar medium. \\

[1] Thorwirth, S., Theul\'{e}, P., Gottlieb, C.A., McCarthy, M.C., Thaddeus, P. \textit{Astrophys. J.}, 662, 1309-1314, \textbf{2007}.

[2] Keutsch, F.N., Cruzan, J.D., Saykally, R.J. \textit{Chem. Rev.}, 103, 2533-2577, \textbf{2003}.