Infrared spectra of water clusters in krypton and xenon matrices

Abstract

The infrared absorption spectra of the water molecules and small water clusters, (H(2)O)(n) with n = 2-6, trapped in solid argon, krypton, and xenon matrices have been investigated. The infrared bands of the water clusters with n = 5 and 6 in krypton and n = 3, 4, 5, and 6 in xenon matrices have been identified for the first time in the bonded OH stretching region. The frequency shifts in the bonded OH stretching band of the water dimer and trimer in xenon matrices show fairly large deviations to the red from the empirical correlation between the matrix shifts and the square root of the critical temperatures of the matrix material. The observed anomalous shifts suggest that the water dimer and trimer in solid xenon are trapped in multiple sites, and that the structures of the preferential trapping sites are different from those in argon and krypton matrices.

Infrared spectroscopy of water clusters isolated in methane matrices: Effects of isotope substitution and annealing

“…In previous studies using liquid He droplets 33 and matrices of para-H 2 , 2 Ne, 4 and Ar, 3 two absorption peaks in the frequency range of 3515−3545 cm −1 were both attributed to the cyc-trimer, but one of the present authors argued that both of them are not likely to originate from the same isomer of the trimer, taking into account their frequency difference and temperature dependence. 10 TABLE III.…”

“…As r gets larger, the peaks at 3360, 3323, and 3218 cm −1 become visible. On the basis of the assignment in previous studies using liquid He droplets 21 and matrices of para-H 2 , 2 Ne, 4 Ar, Kr, and Xe, 3 the peaks at 3360 and 3323 cm −1 are assigned to the cyc-isomers of the tetramer and pentamer, respectively. In each of these studies, an infrared band was observed within the range of 3200−3230 cm −1 and was attributed to cage hexamer.…”

“…The filled circles, matrices of polyatomic molecules of para-H 2 , 2,6,7 D 2 , 8 N 2 , 9 CH 4 , and CD 4 ; the open circles, rare gas matrices of He, Ne, 4,6,7 Ar, 3,[5][6][7] and Kr. 3,5 The results of linear fitting are denoted by solid (broken) lines for the data represented by closed (open) circles.…”

“…This shoulder grows rapidly as r becomes larger. Therefore, taking into consideration the r dependence of the bonded-OH peak intensities, we assign the features at 3690 and 3682 cm −1 to the free OH vibrations of (H 2 O) 3 and (H 2 O) n with n = 4−6, respectively. On the other hand, we attribute the 3630 cm −1 peak to the symmetric stretch (ν s ) and the 3720 cm −1 one with a shoulder at 3710 cm −1 to the antisymmetric stretch (ν as ) of the monomer.…”

“…1 Because host materials are required to be inert in order for the formation of isolated water clusters, the infrared-inactive matrix species of rare gases [2][3][4][5][6][7] and homonuclear diatomic molecules 2,8,9 have been mainly used. On the other hand, Yamakawa and Fukutani measured infrared spectra of water clusters in an adsorption layer of H 2 on a deposited NaCl film, and successfully detected infrared absorption due to the two-dimensional matrix of H 2 in addition to that due to the clusters.…”