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Liu Z, Li X, Ge M, Zheng R, Duan C. Structural characterization of the NO(X 2Π)-N 2O complex with mid-infrared laser absorption spectroscopy and quantum chemical calculations. J Chem Phys 2020; 152:154303. [PMID: 32321260 DOI: 10.1063/1.5144648] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Both positive and negative ions of N3O2 have been observed in various experiments. The neutral N3O2 was predicted to exist either as a weakly bound NO·N2O complex or a covalent molecule. The rovibrational spectrum of the NO(X2Π)-N2O complex has been measured for the first time in the 5.3 µm region using distributed quantum cascade lasers to probe the direct absorption in a slit-jet supersonic expansion. The observed spectrum is analyzed with a semi-rigid asymmetric rotor Hamiltonian for a planar open-shell complex, giving a bent geometry with an a-axis-NO angle of about 21.9°. The vibrationally averaged 2A'-2A″ energy separation is determined to be ε = 144.56(95) cm-1 for the ground state, indicating that the electronic orbital angular momentum is partially quenched upon complexation. Geometry optimizations of the complex restricted to a planar configuration at the RCCSD(T)/aug-cc-pVTZ level of theory show that the 2A″ state is more stable than the 2A' state by about 110 cm-1 and the N atom of NO points to the central N atom of N2O at the minimum of the 2A″ state.
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Affiliation(s)
- Zhuang Liu
- College of Physical Science and Technology, Central China Normal University, Wuhan 430079, China
| | - Xiang Li
- College of Physical Science and Technology, Central China Normal University, Wuhan 430079, China
| | - Murong Ge
- College of Physical Science and Technology, Central China Normal University, Wuhan 430079, China
| | - Rui Zheng
- School of Physics and Electronics, North China University of Water Resources and Electric Power, Zhengzhou 450011, China
| | - Chuanxi Duan
- College of Physical Science and Technology, Central China Normal University, Wuhan 430079, China
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Liu Z, Luo W, Duan C. Mid-infrared laser absorption spectroscopy of the Ne-NO(X 2Π) complex. J Chem Phys 2019; 151:094306. [PMID: 31492078 DOI: 10.1063/1.5115319] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The rovibrational spectrum of the Ne-NO(X2Π) open-shell complex has been measured in the 5.3 µm region using distributed feed-back quantum cascade lasers to probe the direct absorption in a slit-jet supersonic expansion. Three P-subbands (P' ← P″: 1/2 ← 1/2, 3/2 ← 1/2, and 5/2 ← 3/2) were observed, where P is the projection of the angular momentum J along the inertial a-axis of the complex. The hyperfine structure due to the nuclei spin of 14N (I = 1) was partially resolved in the P' ← P″: 1/2 ← 1/2 and 3/2 ← 1/2 subbands. The observed mid-infrared spectrum of Ne-NO (X2Π) together with the previously reported microwave spectrum was analyzed using a modified semirigid asymmetric rotor Hamiltonian for a planar open-shell complex. The band origin is located at 1876.0606(97) cm-1, which is blue-shifted from that of the NO monomer by only 0.0888 cm-1. The complex shows strong structural relaxation upon excitation of the overall rotation and the internal rotation of the NO subunit.
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Affiliation(s)
- Zhuang Liu
- College of Physical Science and Technology, Central China Normal University, Wuhan 430079, China
| | - Wei Luo
- College of Physical Science and Technology, Central China Normal University, Wuhan 430079, China
| | - Chuanxi Duan
- College of Physical Science and Technology, Central China Normal University, Wuhan 430079, China
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Liu Z, Luo W, Duan C. Mid-infrared quantum cascade laser spectroscopy of the Ar-NO complex: Fine and hyperfine structure. J Chem Phys 2019; 150:064302. [PMID: 30769989 DOI: 10.1063/1.5084755] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The rovibrational spectrum of the Ar-NO open-shell complex has been measured in the 5.3 µm region using distributed feed-back quantum lasers to probe the direct absorption in a slit-jet supersonic expansion. Five P-subbands, namely, P'←P″:1/2←3/2,1/2←1/2,3/2←1/2,5/2←3/2, and 7/2←5/2, are observed, with J up to 15.5. The hyperfine structure due to the nuclei spin of 14N (I = 1) can be partially resolved in the P'←P″:1/2←3/2,1/2←1/2, and 3/2←1/2 subbands. The fine structure of the observed spectrum is analyzed using a modified semi-rigid rotor Hamiltonian [W. M. Fawzy and J. T. Hougen, J. Mol. Spectrosc. 137, 154-165 (1989)] and an empirical Hamiltonian [Y. Kim and H. Meyer, Int. Rev. Phys. Chem. 20, 219-282 (2001)] separately. The hyperfine structure can be simulated successfully by including hyperfine terms to the semi-rigid rotor Hamiltonian. A linear J-dependence of the angle between the inertial a-axis of the complex and the intramolecular axis of the NO subunit is also introduced in order to model the strong structure relaxation effect in the P = 1/2 state.
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Affiliation(s)
- Zhuang Liu
- College of Physical Science and Technology, Central China Normal University, Wuhan 430079, China
| | - Wei Luo
- College of Physical Science and Technology, Central China Normal University, Wuhan 430079, China
| | - Chuanxi Duan
- College of Physical Science and Technology, Central China Normal University, Wuhan 430079, China
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Beutner V, Zhang SG, Meyer H, Kłos J. The near-IR spectrum of NO(X̃ 2Π)-He detected through excitation into the Ã-state continuum: A joint experimental and theoretical study. J Chem Phys 2016; 145:124318. [PMID: 27782644 DOI: 10.1063/1.4963228] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present the first measurement of a bound-state spectrum of the NO-He complex. The recorded spectrum is associated with the first overtone transition of the NO moiety. The IR absorption is detected by exciting the vibrationally excited complex to the Ã-state dissociation continuum. The resulting NO(A) fragment is subsequently ionized in the same laser pulse. We recorded two bands centered around the NO monomer rotational lines, Q11(0.5) and R11(0.5), consistent with an almost free rotation of the NO fragment within the complex. The origin of the spectrum is found at 3724.06 cm-1 blue shifted by 0.21 cm-1 from the corresponding NO monomer origin. The rotational structures of the spectrum are found to be in very good agreement with calculated spectra based on bound states derived from a set of high level ab initio potential energy surfaces [Kłos et al. J. Chem. Phys. 112, 2195 (2000)].
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Affiliation(s)
- V Beutner
- Department of Physics and Astronomy, The University of Georgia, Athens, Georgia 30602-2451, USA
| | - S G Zhang
- Department of Physics and Astronomy, The University of Georgia, Athens, Georgia 30602-2451, USA
| | - H Meyer
- Department of Physics and Astronomy, The University of Georgia, Athens, Georgia 30602-2451, USA
| | - J Kłos
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742-2021, USA
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Kłos J, Zhang SG, Meyer H. The near-IR spectrum of NO(X̃(2)Π)-Ne detected through excitation into the Ã-state continuum: A joint experimental and theoretical study. J Chem Phys 2016; 144:114307. [PMID: 27004876 DOI: 10.1063/1.4943797] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present new measurements of the near IR spectrum of NO-Ne in the region of the first NO overtone transition. The IR absorption is detected by exciting the vibrationally excited complex to the Ã-state dissociation continuum. The resulting NO(A) fragment is subsequently ionized in the same laser pulse. Spectra of the two lowest bands, A and B, are recorded. The spectra are compared with calculated spectra based on bound states derived from a new set of high level ab initio potential energy surfaces (PESs). For the calculation, the PESs are used with either fixed NO intermolecular distance or averaged for the vibrational states of NO (X̃, v = 0 or 2). Spectra based on the new PESs reproduce the experimental spectra better than theoretical spectra based on the older PESs of M. H. Alexander et al. [J. Chem. Phys. 114, 5588 (2001)]. Especially, spectra based on the two different vibrationally averaged PESs show a marked improvement in comparison to the one based on the fixed internuclear NO-distance. A fitted set of spectroscopic constants allows to reproduce most of the finer details of the measured spectra. Monitoring simultaneously the NO fragment ion and the parent ion channels while scanning the UV wavelength through the NO A-X hot-band region enabled us to confirm the NO-Ne Ã-state dissociation limit of 44233 ± 5 cm(-1). These measurements also confirm the absence of a structured NO-Ne spectrum involving the Ã-state.
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Affiliation(s)
- J Kłos
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742-2021, USA
| | - S G Zhang
- Department of Physics and Astronomy, The University of Georgia, Athens, Georgia 30602-2451, USA
| | - H Meyer
- Department of Physics and Astronomy, The University of Georgia, Athens, Georgia 30602-2451, USA
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Holmes-Ross HL, Valenti RJ, Yu HG, Hall GE, Lawrance WD. Rotational and angular distributions of NO products from NO-Rg (Rg = He, Ne, Ar) complex photodissociation. J Chem Phys 2016; 144:044309. [PMID: 26827219 DOI: 10.1063/1.4940690] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present the results of an investigation into the rotational and angular distributions of the NO à state fragment following photodissociation of the NO-He, NO-Ne, and NO-Ar van der Waals complexes excited via the à ← X̃ transition. For each complex, the dissociation is probed for several values of Ea, the available energy above the dissociation threshold. For NO-He, the Ea values probed were 59, 172, and 273 cm(-1); for NO-Ne they were 50 and 166 cm(-1); and for NO-Ar they were 44, 94, 194, and 423 cm(-1). The NO à state rotational distributions arising from NO-He are cold, with most products in low angular momentum states. NO-Ne leads to broader NO rotational distributions but they do not extend to the maximum possible given the energy available. In the case of NO-Ar, the distributions extend to the maximum allowed at that energy and show the unusual shapes associated with the rotational rainbow effect reported in previous studies. This is the only complex for which a rotational rainbow effect is observed at the chosen Ea values. Product angular distributions have also been measured for the NO à photodissociation product for the three complexes. NO-He produces nearly isotropic fragments, but the anisotropy parameter, β, for NO-Ne and NO-Ar photofragments shows a surprising change in sign from negative to positive as Ea increases within the unstructured excitation profile. Franck-Condon selection of a broader distribution of geometries including more linear geometries at lower excitation energies and more T-shaped geometries at higher energies can account for the changing recoil anisotropy. Two-dimensional wavepacket calculations are reported to model the rotational state distributions and the bound-continuum absorption spectra.
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Affiliation(s)
- Heather L Holmes-Ross
- School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia
| | - Rebecca J Valenti
- School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia
| | - Hua-Gen Yu
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA
| | - Gregory E Hall
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA
| | - Warren D Lawrance
- School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia
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