Rovibrational structure of the Ar–CO complex based on a novel three-dimensional ab initio potential

Exchange-Coulomb model potential energy surfaces have been developed for the Ne-CO interaction. The initial model is a three-dimensional potential energy surface based upon computed Heitler-London interaction energies and literature results for the long-range induction and dispersion energies, all as functions of interspecies distance, the orientation of CO relative to the interspecies axis, and the bond length of the CO molecule. Both a rigid-rotor model potential energy surface, obtained by setting the CO bond length equal to its experimental spectroscopic equilibrium value, and a vibrationally averaged model potential energy surface, obtained by averaging the stretching dependence over the ground vibrational motion of the CO molecule, have been constructed from the full data set. Adjustable parameters in each model potential energy surface have been determined through fitting a selected subset of pure rotational transition frequencies calculated for the 20 Ne -12 C 12 O isotopolog to precisely known experimental values. Both potential energy surfaces provide calculated results for a wide range of available experimental microwave, millimeter-wave, and midinfrared Ne-CO transition frequencies that are generally far superior to those obtained using the best current literature potential energy surfaces. The vibrationally averaged CO ground state potential energy surface, employed together with a potential energy surface obtained from it by replacing the ground vibrational state average of the CO stretching dependence of the potential energy surface by an average over the first excited CO vibrational state, has been found to be particularly useful for computing and/or interpreting mid-IR transition frequencies in the Ne-CO dimer.

Section: Discussionmentioning

confidence: 99%

Section: The Ne-co Exchange-coulomb Model Potential Surfacementioning

confidence: 99%

An exchange-Coulomb model potential energy surface for the Ne–CO interaction. I. Calculation of Ne–CO van der Waals spectra

Dham

McCourt

Meath

2009

“…Some previous works 11,14 showed that the vibrationally adiabatic potential provides a good explanation for the experiment results. The vibrationally averaged Ne-CO potential can be expressed as…”

Section: B Fitting Proceduresmentioning

confidence: 99%

“…On the theoretical [11][12][13][14][15][16] side, a lot of attentions were attracted on the Rg-CO complexes. For instance, in 2005, Peterson and McBane 11 constructed the three-dimensional PES of the He-CO complex.…”

Section: Introductionmentioning

confidence: 99%

A new ab initio potential energy surface for the NeCO complex with the vibrational coordinate dependence

Wang

Feng

et al. 2011

A new high quality three-dimensional potential energy surface for the Ne-CO van der Waals complex is developed using the CCSD(T) method and avqz/avqz+33221 basis set. The ab initio calculation is performed in a total of 1365 configurations with supermolecule method. There is a single global minimum located in a nearly T-shaped geometry. The global minimum energy is −49.4090 cm −1 at R e = 6.40a 0 and θ e = 82.5• for V 00 . Using the three-dimensional potential energy surface, we have calculated bound rovibrational energy levels up to J = 10 including the Coriolis coupling terms. Compared with the experimental transition frequencies, the theoretical results are in good agreement with the experimental results.

“…1 and the isotropic potential is shown in Panel (e). The CO-Ar potential 33 (Panel (b) of Fig. 1) is the same as used before in our study 25 for isolated CO, with the bond length fixed to r CO = 1.1324 Å in the potential simulation.…”

Section: Rotational Raman Spectrum Of Hmentioning

confidence: 99%

Raman spectroscopy and crystal-field split rotational states of photoproducts CO and H2 after dissociation of formaldehyde in solid argon

Olbert‐Majkut

Pettersson

Kiljunen

2012

Kiljunen, T. (2012). Raman spectroscopy and crystal-field split rotational states of photoproducts CO and H2 after dissociation of formaldehyde in solid argon. The Journal of Chemical Physics, 137 (16), 164310-11. doi:10.1063 Raman signal is monitored after 248 nm photodissociation of formaldehyde in solid Ar at temperatures of 9-30 K. Rotational transitions J = 2 ← 0 for para-H 2 fragments and J = 3 ← 1 for ortho-H 2 are observed as sharp peaks at 347.2 cm −1 and 578.3 cm −1 , respectively, which both are accompanied by a broader shoulder band that shows a split structure. The rovibrational spectrum of CO fragments has transitions at 2136.5 cm −1 , 2138.3 cm −1 , 2139.9 cm −1 , and 2149 cm −1 . To explain the observations, we performed adiabatic rotational potential calculations to simulate the Raman spectrum. The simulations indicate that the splitting of rotational transitions is a site effect, where H 2 molecules can reside in a substitution site, in addition to an interstitial site. In the former site, rotational motion is unperturbed by the electrostatic field of the host atoms, while the latter site splits the excited rotational manifolds, J = 2 and 3, into doublet and triplet structures, respectively. For CO, the spectrum can be ascribed to monomeric species in single-and double-substitution sites, to a dimeric species (CO) 2 , and to a CO-H 2 O complex. The simulations show that a nearest-neighbor molecular complex CO-H 2 is not responsible for any of the observed spectral fingerprints. The cause of the exit of the molecular hydrogen from the initial cage can be traced to high translational energy of the fragment after the photodissociation. After the matrix has reached a thermal equilibrium, a diffusion driven formation of the complex is possibly hindered by the high rotational zero-point energy developed upon complexation.