Infrared Spectra and Intensities of the H₂O and N₂ Complexes in the Range of the ν₁- and ν₃-Bands of Water

Abstract

The IR spectra of complexes of water with nitrogen molecules in the range of the symmetric (nu(1)) and antisymmetric (nu(3)) bands of H(2)O have been studied in helium droplets. The infrared intensities of the nu(3) and nu(1) modes of H(2)O were found to be larger by factors of 1.3 and 2, respectively, in the N(2)-H(2)O complexes. These factors are smaller than those obtained in recent theoretical calculations. The conformation of the N(2)-H(2)O complex was estimated. Spectra and IR intensities of the (N(2))(2)-H(2)O and N(2)-(H(2)O)(2) complexes were also obtained and their structures are discussed.

Infrared Spectra and Intensities of Ar−H2O and O2−H2O Complexes in the Range of the ν3 Band of H2O

“…For comparison, the spectrum of N 2 -H 2 O is also shown in Figure 2a, which was similarly reconstructed from previously reported data. 12 Note that the spectrum in Figure 2a was obtained at the lower pickup pressure of z(H 2 O) ) 0.25 for H 2 O than that in Figure 2b,c.…”

“…40,41 The fact that the IRIs of the Ar-H 2 O and O 2 -H 2 O complexes are found to be almost the same as that of H 2 O itself is consistent with the absence of hydrogen bonds in these complexes. The spectra of the ν 3 band of H 2 O in the Ar-H 2 O and O 2 -H 2 O complexes differ markedly from the spectrum of the N 2 -H 2 O complex,12 as seen inFigure 2. The spectra of the N 2 -H 2 O complex show two bands separated by about 6 cm -1 , which are attributed to the parallel and perpendicular bands of the complex with no internal rotation of H 2 O 12.…”

“…The spectra of the ν 3 band of H 2 O in the Ar-H 2 O and O 2 -H 2 O complexes differ markedly from the spectrum of the N 2 -H 2 O complex,12 as seen inFigure 2. The spectra of the N 2 -H 2 O complex show two bands separated by about 6 cm -1 , which are attributed to the parallel and perpendicular bands of the complex with no internal rotation of H 2 O 12. On the other hand, the spectra of the Ar-H 2 O and O 2 -H 2 O complexes show peaks close to the rovibrational lines of monomeric H 2 O, which clearly indicates that the water molecule in these complexes exhibits nearly free internal rotation.Internal rotation of H 2 O in the Ar-H 2 O complex is welldocumented in the gas phase [17]…”

Rovibrational analysis of the water bending vibration in the mid-infrared spectrum of atmospherically significant N2–H2O complex

“…Furthermore, there have been FTIR studies of N 2 -H 2 O and (H 2 O) n=2-20 -N 2 in the near infrared [11,12]. The spectra of the N 2 -H 2 O complex in helium nanodroplets have also been recorded in the near-infrared (3700-3900 cm −1 ) and show two bands separated by about 6 cm −1 , that are attributed to the parallel and perpendicular bands of the complex with no internal rotation of H 2 O [13]. The harmonic frequencies (and infrared intensities) have been calculated at 70.…”

Rovibrational energies and spectroscopic constants for H2O−Ng complexes

“…It must be pointed that weakly interacting complexes of water in the gas phase yield collisional complexes, either stable or metastable, that can play important roles in atmospheric problems [12]. In particular, complexes concerning water and air components have been suggested as possible contributors to the absorption of solar radiation [13,14], thus disturbing the Earth atmosphere energy balance. Detailed description of dynamical and optical properties of such weakly interacting systems is still unsatisfactory [15].…”