Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5428212 | Journal of Quantitative Spectroscopy and Radiative Transfer | 2014 | 13 Pages |
â¢VUV spectroscopy of N2O in 45,000-95,000 cmâ1 region using synchrotron radiation.â¢TDDFT computations of excited states, oscillator strengths, potential energy curves.â¢Features in 45,000-60,000 cmâ1 region assigned to hot band progressions of Ï 2â². QUOTEâ¢Vibronic structure in 60,000-72,000 cmâ1 region explained by Renner-Teller effect.â¢First assignment of 3d Rydberg and vibronic transitions in 85,000-95,000 cmâ1 region.
We report a comprehensive photoabsorption study of nitrous oxide (N2O) in the vacuum ultraviolet (45,000-95,000 cmâ1) region using synchrotron radiation. The observed spectrum comprises of a few valence transitions and low lying Rydberg series converging to the two spin-orbit components (2Ð1/2,3/2) of the ground state of N2O+. Spectral analysis is aided by extensive quantum chemical calculations of vertical excited states, oscillator strengths and potential energy curves using the time dependent density functional theory. Vibronic bands observed in the first absorption system (45,000-60,000 cmâ1) are assigned to hot band progressions in Ï 2â² originating from vâ³=1 or 2. New insights into the assignment of the well-formed progression of bands in the X1Σ+âC1Ð system (60,000-72,000 cmâ1) are afforded by consideration of the Renner-Teller interaction. A set of molecular vibrational parameters (Ï2=467 cmâ1, x22=â2.9, ε=â0.24) for the C1Ð state are derived from a fitting of the experimental data. The 3pÏ1Σ+ state at ~77,600 cmâ1 shows a large quantum defect (0.96) which is explained as arising due to mixed valence-Rydberg character. In the 85,000-95,000 cmâ1 region, a number of absorption features are observed with greater clarity than in earlier photoabsorption studies and assigned to Rydberg series of type nlλ (n=3,4; l=s,p,d; λ=Ï,Ï,δ) and accompanying vibronic bands. This work has resulted in clarification of several discrepancies in earlier Rydberg series assignments. Additionally, the 3pÏ 3Σâ Rydberg state at 85,788 cmâ1, the valence transition 7Ïâ3Ï (1Ð) at 87,433 cmâ1 and the 3dλ Rydberg series in the 91,700-92,600 cmâ1 region are assigned for the first time.