Experimental and theoretical investigations of H2O–Ar

Abstract

We have used continuous-wave cavity ring-down spectroscopy to record the spectrum of HO-Ar in the 2OH excitation range of HO. 24 sub-bands have been observed. Their rotational structure (T = 12 K) is analyzed and the lines are fitted separately for ortho and para species together with microwave and far infrared data from the literature, with a unitless standard deviation σ=0.98 and 1.31, respectively. Their vibrational analysis is supported by a theoretical input based on an intramolecular potential energy surface obtained through ab initio calculations and computation of the rotational energy of sub-states of the complex with the water monomer in excited vibrational states up to the first hexad. For the ground and (010) vibrational states, the theoretical results agree well with experimental energies and rotational constants in the literature. For the excited vibrational states of the first hexad, they guided the assignment of the observed sub-bands. The upper state vibrational predissociation lifetime is estimated to be 3 ns from observed spectral linewidths.

Cross Second and Third Virial Coefficients and Dilute Gas Transport Properties of the (H2O + Ar) System from First-Principles Calculations

“…The PES features a single minimum with a depth of 209.0 K at R = 3.648 Å, θ = 106.2°, and ψ = 90.0°. The ab initio PESs of Hodges et al (206 K), Makarewicz (203 K), Hou et al (201 K), Vanfleteren et al (201 K), and Liu et al (202 K) and the spectroscopically based PES of Cohen and Saykally (206 K) are all somewhat shallower. In the case of the listed ab initio PESs, this is partly due to the fact that post-CCSD­(T) contributions and relativistic effects were not considered in their development.…”

Insight into the Binding of Argon to Cyclic Water Clusters from Symmetry-Adapted Perturbation Theory

“…The interaction between an Ar atom and a single H 2 O molecule has been studied in great detail [69,[79][80][81][82][83][84][85][86][87][88][89][90][91][92][93], but relatively few studies have looked at the interactions of Ar with the water dimer [69,87,94] or larger water clusters [95,96]. The present study systematically identifies the energetically favorable binding sites of a single Ar atom to the well-characterized structures of cyclic (H 2 O) n=3-5 clusters [6,10,24,30,31,37,42, while also tracking structural and vibrational perturbations that occur.…”

Production of Br2from N2O5and Br–in Salty and Surfactant-Coated Water Microjets

“…Figure 3a shows that Ar atoms desorb from the jet in an approximate Maxwell− Boltzmann (MB) distribution that is fit to a temperature of 263 K, along with fits at ±15 K. None of the MB fits are exact because the Ar atoms expand slightly supersonically through the vapor cloud, implying that some evaporating Ar and H 2 O collide as they exit the jet. 8,10,53,54 Figure 3b illustrates that water molecules themselves evaporate in a more developed supersonic expansion because of the larger cross section for water−water collisions in the jet vapor cloud. 7 This distribution is more Maxwellian at 240 K than at 263 K because of the drop in water vapor pressure from 2.1 to 0.4 Torr.…”