摘要:
The rovibrational spectrum of the NO(X-2 Pi)-CO2 open-shell complex has been measured in the fundamental band region of NO using an infrared laser absorption spectrometer. Geometry optimizations at restricted configurations with a C-s symmetry at the RCCSD(T)/aug-cc-pvtz level of theory predict that this complex has a T-shaped structure at the global minimum on the ground electronic state ((2)A ''), with the N atom of NO pointing to the C atom of CO2. The observed spectrum is analyzed with an effective Hamiltonian for a planar T-shaped open-shell complex. Half of the possible rotational levels are missing due to spin statistics of the two identical O-16 nuclei (I = 0) in the CO2 subunit of the complex. The band-origin of the complex is located at 1880.4518(67) cm(-1), which is blue-shifted from that of the NO monomer by about 4.48 cm 1. The rotational constants and the quenching parameter of the electronic orbital angular momentum of NO in both ground and excited vibrational states have been determined accurately. The intermolecular distance between centers of mass of CO2 and NO in the ground state is determined to be R = 3.703 angstrom. (C) 2020 Elsevier Inc. All rights reserved.
摘要:
Rovibrational spectra of Ar-N2O and nonpolar (N2O)(2) van der Waals complexes have been recorded from 1157.2 to 1176.7 cm(-1) in 2v(2) overtone band region of N2O monomer using an external-cavity quantum cascade laser to probe the direct absorption in a slit supersonic jet expansion. One a/b hybrid vibrational band was identified for nonpolar (N2O)(2), and one b-type vibrational band for Ar-N2O, respectively. Quantum chemical calculations of vibrational frequencies and infrared intensities of these two complexes were performed at the MP2/aug-cc-pvtz level of theory. The first vibrational band is assigned tentatively as a combination band of the intramolecular symmetric and anti-symmetric in-plane bending modes of nonpolar (N2O)(2). The second vibrational band is assigned as an overtone band of the bending mode of Ar-N2O. Precise molecular constants have been derived for these two complexes. The band-origin is located at t(0) = 1168.177584(76) cm(-1) for Ar-N2O and t(0) = 1165.218580(54) cm(-1) for nonpolar (N2O)(2), which shows a blue-shift by 0.0451 cm(-1) for Ar-N2O and a red-shift by 2.9139 cm(-1) for nonpolar (N2O)(2) compared with that of the N2O (0200)-(0000) band, respectively. (C) 2021 Elsevier Inc. All rights reserved.
作者机构:
[Duan, Chuanxi; Ge, Murong; Liu, Zhuang; Li, Xiang] Cent China Normal Univ, Coll Phys Sci & Technol, Wuhan 430079, Peoples R China.;[Zheng, Rui] North China Univ Water Resources & Elect Power, Sch Phys & Elect, Zhengzhou 450011, Peoples R China.
通讯机构:
[Duan, Chuanxi] C;Cent China Normal Univ, Coll Phys Sci & Technol, Wuhan 430079, Peoples R China.
摘要:
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.
作者机构:
[Duan, Chuanxi; Liu, Zhuang; Luo, Wei] Cent China Normal Univ, Coll Phys Sci & Technol, Wuhan 430079, Hubei, Peoples R China.
通讯机构:
[Duan, Chuanxi] C;Cent China Normal Univ, Coll Phys Sci & Technol, Wuhan 430079, Hubei, Peoples R China.
关键词:
argon;hyperfine structure;infrared spectra;nitrogen compounds;rotational-vibrational states
摘要:
The rovibrational spectrum of the Ar-NO open-shell complex has been measured in the 5.3 microm 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 (14)N (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.
作者机构:
[Duan, Chuanxi; Liu, Zhuang; Luo, Wei] Cent China Normal Univ, Coll Phys Sci & Technol, Wuhan 430079, Hubei, Peoples R China.
通讯机构:
[Duan, Chuanxi] C;Cent China Normal Univ, Coll Phys Sci & Technol, Wuhan 430079, Hubei, Peoples R China.
关键词:
hyperfine structure;infrared spectra;organic compounds;rotational-vibrational states
摘要:
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.
作者机构:
[Duan, ChuanXi; Wei, MingZheng] Cent China Normal Univ, Coll Phys Sci & Technol, Wuhan 430079, Hubei, Peoples R China.;[Zhao, Meng; Zhou, Yu; Xu, SongPo; Liu, XiaoJun; Quan, Wei; Wei, MingZheng; Sun, RenPing; Xiao, ZhiLei] Chinese Acad Sci, State Key Lab Magnet Resonance & Atom & Mol Phys, Wuhan Inst Phys & Math, Wuhan 430071, Hubei, Peoples R China.;[Zhao, Meng; Zhou, Yu; Xu, SongPo; Liu, XiaoJun; Quan, Wei; Wei, MingZheng; Sun, RenPing; Xiao, ZhiLei] Chinese Acad Sci, Ctr Cold Atom Phys, Wuhan Inst Phys & Math, Wuhan 430071, Hubei, Peoples R China.;[Zhou, Yu; Xu, SongPo; Sun, RenPing; Xiao, ZhiLei] Univ Chinese Acad Sci, Sch Phys, Beijing 100080, Peoples R China.;[Zhao, Meng] Wuhan Univ Sci & Technol, Hubei Prov Key Lab Syst Sci Met Proc, Wuhan 430081, Hubei, Peoples R China.
通讯机构:
[Quan, Wei] C;Chinese Acad Sci, State Key Lab Magnet Resonance & Atom & Mol Phys, Wuhan Inst Phys & Math, Wuhan 430071, Hubei, Peoples R China.;Chinese Acad Sci, Ctr Cold Atom Phys, Wuhan Inst Phys & Math, Wuhan 430071, Hubei, Peoples R China.
摘要:
Experimentally and theoretically, we explore the photoelectron momentum distributions of N2 and O2 and their companion atoms Ar and Xe, which possess nearly equal electron binding energies to the corresponding molecules, subject to close-to-circularly polarized laser fields. Compared to Xe, significant deviations of the results for O2 have been observed experimentally. In the meantime, the measured photoelectron momentum distributions of N2 match those of Ar. With the theoretical analysis based on strong field approximation, the results that N2 behaves just like its companion atom Ar and O2 behaves significantly different from Xe have been attributed to the two-center interference effect of diatomic molecules, which is disparate for N2 and O2 due to the parity difference of their molecular ground-state wave functions.
关键词:
ab initio calculations;argon compounds;bonds (chemical);bound states;carbon compounds;coupled cluster calculations;helium compounds;isomerism;neon compounds;potential energy surfaces;rotational states;rotational-vibrational states;vibrational states;wave functions
摘要:
Theoretical studies of the potential energy surfaces (PESs) and bound states are performed for rare gas-carbon disulfide complexes, He-CS2, Ne-CS2, and Ar-CS2. Three two-dimensional intermolecular PESs are constructed from ab initio data points which are calculated at the CCSD(T) level with aug-cc-pVTZ basis set supplemented with bond functions. We find that the three PESs have very similar features and each PES can be characterized by a global T-shaped minimum, two equivalent local linear minima, and the saddle points between them. The T-shaped isomer is energetically more stable than the linear isomer for each complex. The linear isomers, which have not been observed in experiment so far, are predicted from our PESs and further identified by bound state calculations. Moreover, we assign several intermolecular vibrational states for both the T-shaped and linear isomers of the three complexes via the analysis of wavefunctions. The corresponding vibrational frequencies are calculated from the bound state energies for these assigned states. These frequencies could be helpful for further experimental studies, especially for the linear isomers. We also calculate the rovibrational transition frequencies for the three T-shaped isomers and the pure rotational transition frequencies for the linear isomers, respectively. The accuracy of the PESs is validated by the good agreement between theoretical and experimental results for the rovibrational transition frequencies and spectroscopic parameters.
摘要:
<正>Formic acid dimer is a prototype for studying the double-proton transfer dynamics in multiple hydrogen-bonded systems. The IR high resolution jet spectrum of the formic acid dimer has been recorded in the region of the antisymmetric C-O stretch vibration at 1210 - 1250 cm-1 . The previous study suggested
摘要:
The rovibrational spectrum of H2O–CO2 and D2O–CO2 weakly bound complexes has been measured in the v2 bend region of the water monomer by infrared diode laser absorption spectroscopy. Rotational and centrifugal distortion constants for different internal rotation states in the excited vibrational state have been determined. The band-origin of the spectrum is blue-shifted from that of the water monomer by 0.739 cm−1 for H2O–CO2 and 0.083 cm−1 for D2O–CO2, respectively. The tunneling splitting is reduced upon vibrational excitation by 0.00698(31) cm−1 for H2O–CO2 and 0.00044(17) cm−1 for D2O–CO2, respectively.