The Study Of The Potential Energy Surface And Bound States Infrared Spectra For Kr-N₂O In The V₁Stretching Region Of N₂O The Kr-N₂O Complex

N2O is one of the primary greenhouse gases implicated in global warming. And N2O is a precursor for the production of nitrogen oxides NOx, which play an important role in stratospheric ozone chemistry. The van der Waals (vdW) interaction between N2O and a rare-gas (Rg) atom has been the active object of both experimental and theoretical studies recently.In this thesis, we have recorded a three-dimensional potential energy surface and predicted infrared spectra for the Kr-N2O and Ne-N2O complex in the v1stretching region of N2O.(1) The single and double excitation coupled-cluster method with a noniterative perturbation treatment of triple excitations [CCSD(T)] was employed to calculate the intermolecular potential energy. The basis set was taken as the augmented correlation-consistent polarized valence triple-zeta (aug-cc-pVTZ) basis set of Woon and Dunning for the N and O atoms and the quasirelativistic10-core-electron pseudopotential plus augmented correlation-consistent polarized valence quadruple-ξ (aug-cc-pVQZ-PP) basis set for the Kr atom, supplemented with an additional set of bond functions (3s3p2dlf). The three-dimensional PES is produced via a two-step procedure. In the first step, an analytical two-dimensional model potential is presented to fit numerically to the computed single point energies at each of seven fixed Q1values. The seven two-dimensional potentials are then used in the second step to construct the three-dimensional PES by interpolating along Q1using a six-order polynomial.(2) Based on the three-dimensional PES, two vibrationally averaged PESs of the complex are generated by integral over the Q1normal coordinate. The two vibrational adiabatic surfaces are further used to calculate the bound rovibrational states and the infrared spectrum for the complexes. Each potential is characterized by a global T-shaped minimum and a linear minimum. For the Kr-N2O complex, the global minimum of V0(R,θ) locates at R=6.71a0and θ=87.37°with a depth of-253.69cm-1. Contour plots of the V1surfaces shows the same overall features, although it has slightly shallower minimum. Its global minimum locates at R=6.71a0and θ=87.32°with a depth of-253.55cm-1. For the Ne-N2O complex, the potential V0has a minimum of-104.94cm-1with R=5.82a0at an approximate T-shaped geometry(θ=88.08°).V1has a single nearly T-shaped minimum of at R=5.80a0and θ=88.01°.(3) The two vibrational adiabatic surfaces are further used to calculate the bound rovibrational states and the infrared spectrum for the complexes. The resulting potentials provide a good representation of the experimental data:for119infrared transitions of84Kr-N2O complex, the root mean square deviation is only about0.078cm-1. Our evaluated transition frequencies agree excellently with the observed values with a root mean square error of about0.036cm-1for20Ne-N2O and0.037cm-1for22Ne-N2O. The calculated spectroscopic constants are in good agreement with the available experiment values.