Direct Absorption Spectroscopy of Water Clusters

Abstract

Fourier Transform infrared spectrometry has been used to study the vibrational spectroscopy of water clusters prepared in a supersonic expansion. The clusters are assigned as being composed of 10−100 waters based on consideration of the free OH and bound OH vibrations and the experimental conditions used. Four vibrational features were observed simultaneously including the bend, free OH stretch, bound OH stretch, and an unresolved group of intermolecular vibrations. No absorption features were observed between 4000 and 8000 cm-1. This is the first observation of the bending vibration for any size gas-phase water cluster.

Far-infrared laser vibration–rotation–tunneling spectroscopy of water clusters in the librational band region of liquid water

“…[32][33][34] The free hydrogens in small water clusters-the main distinction of water clusters from the bulk-are predicted not to influence the librational motions to a large degree, and recent low resolution librational band spectra for water clusters containing 10-100 molecules do resemble bulk spectra. 35 Furthermore, computer simulations by Luzar and Chandler indicate that the hydrogen bond dynamics in liquid water are fairly insensitive to both the local hydrogen bond order and the effect of chemical environment, citing the example of a dimethylsulfoxide ͑DMSO͒ water system. [32][33][34] The fact that librational motions are thus very local and insensitive to the specific environment allows small water clusters to serve as models for elucidating the librational dynam-a͒ Author to whom correspondence should be addressed.…”

Ab initio study of bending modes in water cage clusters, (H2O)n, n6–10

“…Recently, these investigations received a boost from new experimental studies on gaseous clusters. The studies focus predominantly on the OH stretch spectral region for both pure clusters 13–21 and clusters connected to benzene 22, 23 and phenol 24, 25 chromophores. The OH stretch spectra are an attractive probe of hydrogen bonding, because strong H‐bonds generate large negative frequency shifts of hundreds of inverse centimeters, with concurrent large increase of the infrared absorption intensity.…”

Improved stability of water clusters (H2O)30–48: a Monte Carlo search coupled with DFT computations

“…Water nanoclusters are crucial building blocks of bulk model systems for explaining the anomalous properties of water [11,12]. However, only indirect experimental information, such as the infrared spectra (IR) [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] and photoelectron spectra [33][34][35][36][37][38][39][40][41], is available for size-nonspecific water clusters. Accordingly, great efforts were devoted to simulating IR spectra in order to assist experiments [42][43][44][45].…”