INFRARED SPECTROSCOPY OF (CH$_3$)$_3$N-H$^+$-(H$_2$O)$_n$ (n $=$ 1-22)

Abstract

The magic number behavior of H$^+$(H$_2$O)$_{21}$ has been well known. Futhermore, this magic number is observed even in the mixed clusters H$^+$(H$_2$O)$_m$(NH$_3$)$_n$ and H$^+$(H$_2$O)$_m$(MeOH)$_n$ (m $+$ n $=$ 21). This means that NH$_3$ or MeOH molecules are compatible with water molecules in the hydrogen bond network of the magic number cluster.\ In the present study, infrared spectroscopy is applied to (CH$_3$)$_3$N-H$^+$-(H$_2$O)$_n$ (n $=$ 1-22), and structures of these clusters are determined with help of density functional theory calculations. As a result, it is demonstrated that no magic number is seen in the case of (CH$_3$)$_3$N-H$^+$-(H$_2$O)$_n$. (CH$_3$)$_3$N is not a spectator to the hydrogen bond network of protonated water clusters, and it is largely changes the network structure.