空气介质阻挡放电中氮分子离子的转动温度研究

采用液体电极装置,首次在空气介质阻挡放电中观察到了清晰分辨的氮分子离子第一负带(0,0)转动谱.根据转动光谱的强度分布,确定转动能级上粒子最大布居数位置,估算了氮分子离子的转动温度.改变外加电压和放电气体的气压,研究了转动温度的变化,发现当气压在10.133～60.795 kPa范围时,随电压的增加,谱线强度增加,但其转动光谱的强度分布不变,说明转动温度保持不变.上述结果对于空气介质阻挡放电理论模型的建立及工业应用均具有重要的参考价值.     

An analog of the Ladenburg-Levi function for the electron-vibrational band of a diatomic molecule

An expression is obtained for the analog of the Ladenburg-Levi function for the electron-vibrational band of a diatomic molecule under the following assumptions: 1) the profile of the rotational line in the band is Dopplerian; 2) the population of the rotational levels is governed by the Boltzman law; 3) the rotational lines in the band do not overlap; 4) we consider transitions between electron states, in which the change of the orbital quantum number is zero. The given function can be used in processing the results of measurements obtained by the method of a single mirror behind a tube, the method of two tubes, etc., during a discharge in molecular gases.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, Vol. 15, No. 6, pp. 24–29, June, 1972.All numerical calculations were performed by S. G. Nosovtsev, whom the authors thank.     

The Use of the Isotope Effect in Rotational Analysis

We draw attention to a method of analyzing single bands with only P and R branches using the isotope effect on the rotational lines. The method is described in detail and applied to the analysis of the 0-0 band of the A O⁺ - X O⁺ transition of InBr. The band origin and rotational constants for both In⁷⁹Br and In⁸¹Br are found to be in excellent agreement with values obtained by more conventional methods of analysis.     

Absolute frequency measurements of N2O laser transitions

The absolute frequencies of 33 P- and R-branch lines of the N₂O, 00°1–10°0 laser band have been measured by heterodyning with known CO₂ laser frequencies of the 00°1 – 10°0 band in a tungsten-nickel diode. These measurements were used to calculate more precise values for the band centre and for the rotational constants.     

精确研究NbN分子d~1∑~+—b~1∑~+电子态跃迁的P线系发射光谱

本文利用最近建立的能精确求解双原子分子P线系发射光谱的物理新公式,研究了NbN分子从电子态d~1∑~+向b~1∑~+电子态跃迁中(1,1)跃迁带的P支发射光谱.获得的计算结果不仅很好地重现了已知低转动态的实验谱线数据,同时也预言了该跃迁带包含转动量子数J=80在内的高振转激发态的精确P线系发射光谱.该方法在理论上为实验技术难以精确测量的双原子分子体系提供了一种获得精确的高激发态谱线数据的物理新方法.从而可以为那些需要NbN分子高激发态跃迁谱线的研究工作提供必要的数据.     

High resolution spectroscopy of the ν3 band of the van der Waals complex Ar—DCOOH

The vibrational-rotational spectrum of the van der Waals complex Ar-DCOOH has been recorded in the spectral region of the carbonyl stretch band. This work represents the first rotationally resolved vibrational spectrum for this complex. A full set of molecular constants could be deduced by fitting 105 lines with a standard S-reduced Watson Hamiltonian. The band origin was determined to be 1725.8440(1)cm^?1 which corresponds to a small red shift of 0.0309cm^?1 compared to the monomer band. The rotational constants deviate only slightly from the rotational constants in the ground state, as determined by microwave spectroscopy (I. I. Ioannou and R. L. Kuczkowski, 1993, J. phys. Chem., 98, 2231).     

Calculation and analytical representation of self-pressure and air pressure broadening coefficients of ozone spectral lines

The coefficients γ of broadening by self-pressure, and pressure of nitrogen, oxygen, and air are calculated for absorption lines of the rotational band and for the ν₂ band of the ozone molecule for temperatures 296, 252, and 212 K. The calculations are performed by the semiclassical method using rectilinear and exact trajectories for interacting molecules. It is shown that the experimental data obtained for the two bands at T = 296 K can be reconstructed better using different isotropic intermolecular interaction potentials. The experimental and calculated broadening coefficients of ozone absorption lines for the rotational band and for the ν₂ and ν₁ + ν₃ vibrational bands were used to determine the parameters of an analytical model, which permits one to calculate γ in a wide range of rotational quantum numbers, 0 ≤ J ≤ 45, 0 ≤ K _a ≤ 20, and temperatures of 200–296 K.     

Diode Laser Spectrum of the ν1 Fundamental Band of PNO

The diode laser spectrum of the ν₁ fundamental band of the short-lived molecule PNO has been detected with 59 R- and P-branch lines accurately measured. The lines were unambiguously assigned using the rotational and distortion constants for the ground and (100) vibrational levels found previously by microwave spectroscopy. The band origin was determined to be 860.301 228(31) cm⁻¹ from a one parameter fit. The gas phase band origin is red-shifted by approximately 4 cm⁻¹ from the matrix value.     

Measurements of temperatures and OH-concentrations in a lean methane-air flame using high-resolution laser-absorption spectroscopy

Line profile measurements of selected spectral lines in the 1-0 band of the A²Σ⁺-X²π system of OH near 2830 Å, using a tunable, frequency-doubled dye laser, have been made to determine simultaneously the translational temperature and hydroxyl concentration in a laminar, flat methane-air flame. The rotational temperature was determined from the ratio of two line-absorption coefficients. The rotational degree of freedom was found to be in equilibrium with the translational degree of freedom. Values deduced for the collision broadening parameter in the 1-0 band depend on OH-concentration, ground state rotational quantum number and, possibly, on the vibrational quantum number.     

High resolution optogalvanic spectrum of N2-rotational structure of (11, 7) band in the first positive system

High resolution optogalvanic spectrum of the (11, 7) band in the first positive system of nitrogen molecule has been recorded from 17179 to 17376 cm⁻¹. Assignment of 432 rotational lines belonging to the 27 branches of this band has been carried out.     

Conversion electron cascades in 254(102)No

The spectrum of prompt conversion electrons emitted by excited 254No nuclei has been measured, revealing discrete lines arising from transitions within the ground state band. A striking feature is a broad distribution that peaks near 100 keV and comprises high multiplicity electron cascades, probably originating from M1 transitions within rotational bands built on high K states.     

Rotational relaxation of the 0001 level of CO2 including radiative transfer in the 4.3-μm band of planetary atmospheres

Accurate numerical solutions have been obtained for a model problem of rotational relaxation within the 00⁰1 vibrational level of C¹²O₂¹⁶ accounting for the transfer of radiation in the lines of the fundamental transition 00⁰1-00⁰0 of the 4.3-μm band. Intramolecular exchange of vibrational energy with the reservoir of v₂ quanta and absorption of solar radiation in the 00⁰1- 00⁰0 band are accounted for. A plane-parallel isothermal atmosphere of pure CO₂ with the barometric pressure distribution and solar illumination is assumed. The line opacity is represented by nonoverlapping Voigt profiles depending on temperature and pressure. The transfer problem, which is equivalent to that of a multiplet with a large number of lines with a common lower level, was solved by a generalization of the Rybicki method. We find significant deviations from ratational LTE (local thermodynamic equilibrium) in regions in which the harmonic average of the optical depth over the band is of order 10³-10⁴. Absorption of solar radiation can affect significantly the source functions of lines at the centers of the P and R branches. Deviations from rotational LTE are shown to influence the intensity and shape of the 4.3-μm band of CO₂ in the spectra of Mars and Venus, and should be taken into account in the interpretation of the observations in which the rotational structure is resolved, especially in limb measurements, where these effects are particularly apparent.     

Single mode multiline emission from a hybrid CO2 laser

A simple technique of obtaining single mode multiline emission from a hybrid CO₂ laser is described. This involves operation of its low pressure section below lasing threshold and a judicious positioning of the axial modes with respect to the corresponding rotational line centres. Emission with comparable intensities on up to four rotational lines in the P-branch of the 10 μm band has been achieved.     

Line coupling in the temperature and frequency dependences of absorption in the microwindows of the 4.3 μm CO2 band

The shapes of the self- and N₂-broadened ν₃CO₂ fundamental vibration-rotation band in the microwindows (troughs between the lines) have been measured at various temperatures. Important deviations with respect to the superposition of Lorentzian profiles are observed. These deviations are interpreted in terms of line coupling, which redistributes the intensity in the whole band. In order to take into account this line coupling, two models are considered within the frame of the impact theory. The first model uses the strong-collision approximation to describe the rotational energy transferred by collisions. It leads to a simple analytical expression for the band profile. The second model is based on the exponential-gap law. These two models account well for the frequency dependence of the measured absorption in the microwindows and for the temperature dependence in the case of the N₂-broadened CO₂ band but not in the self-broadened case. The influence of the line-coupling rotational distribution, which differs significantly in the two models, is discussed. The possible role of the finite duration of collision in rotational energy transfer is examined.     

Spectroscopic study of rotational energy distribution of BH (A 1Π) and electronic excitation temperature determination

Emission spectra of BH(A ¹Π-X ¹Σ⁺) system were recorded and studied using a low pressure (3.0 torr) arc in flowing hydrogen and argon + hydrogen mixture. The rotational distributions in theA ¹Π state determined from the intensities of rotational lines for the 0–0 band of theA-X system conforms to a Maxwellian distribution with effective rotational temperature of 1000 ± 50°K. Intensities of Balmer lines of hydrogen were measured and used to determine electronic excitation temperature which was found to be around 2000°K.     

Universal functions for estimating total vibration-rotation band absorptance—I. Linear molecules and spherical tops

We estimate total band absorptances and their derivatives for nonoverlapping lines of vibration-rotation bands for linear molecules and spherical tops. We use universal functions obtained by replacing the sums of line contributions by integrals over the rotational quantum numbers. An optical path is introduced for the total band. Only general information is utilized on vibrational transitions and line shapes. Power and asymptotic series have been obtained for Doppler and Lorentz line shapes. For a linear molecule and the Lorentz shape, approximate formulae have been derived for the universal functions.     

连续波DF化学激光器光斑上下游光谱测量

通过分析非稳腔DF化学激光器光腔内激光路径特性,指出非稳腔DF化学激光器输出光斑上下游光谱振荡路径不同导致输出光谱存在一定差异。试验测量了一台连续波DF化学激光器光斑上下游光谱,结果表明：非稳腔DF化学激光器光斑上下游光谱主要谱线成分未见显著差异;光斑上下游谱线相对强度存在一定差异;光斑上游各谱带相对强度最大值谱线转动量子数趋向于各谱带低转动量子数方向。根据实测光谱,对光斑上下游光谱所表征光腔温度和相对粒子数范围进行了估算,得到光腔上游平均温度要低于光腔下游平均温度。     

连续波DF化学激光器光斑上下游光谱测量

通过分析非稳腔DF化学激光器光腔内激光路径特性,指出非稳腔DF化学激光器输出光斑上下游光谱振荡路径不同导致输出光谱存在一定差异。试验测量了一台连续波DF化学激光器光斑上下游光谱,结果表明:非稳腔DF化学激光器光斑上下游光谱主要谱线成分未见显著差异;光斑上下游谱线相对强度存在一定差异;光斑上游各谱带相对强度最大值谱线转动量子数趋向于各谱带低转动量子数方向。根据实测光谱,对光斑上下游光谱所表征光腔温度和相对粒子数范围进行了估算,得到光腔上游平均温度要低于光腔下游平均温度。     

The nu(2) Band of Formaldehyde-d(2)

High-resolution Fourier transform infrared spectrum of the nu(2) band (1590-1780 cm(-1)) of deuterated formaldehyde D(2)CO has been recorded. More than 2500 rovibrational transitions have been assigned up to J(max) = 52 and K(max)(a) = 17. The upper state v(2) = 1 (A(1)) was found to be perturbed by a DeltaK(a) = 2 interaction with the v(4) = 2 (A(1)) state. To explain the resonance perturbation in the v(2) = 1 state, some lines of the 2nu(4) band (the band center at about 1868 cm(-1)) have also been assigned. Both bands were fitted simultaneously to the Watson-type rotational Hamiltonian using I(r) representation in A reduction, and the mutual interaction was taken into account. As a result, the rotational parameters of the v(2) = 1 state up to eighth order and the interaction parameter have been obtained. Copyright 2001 Academic Press.     

Observation of the fast component in the fluorescence of gaseous SO2 excited to the A1A2 state in the presence of a magnetic field

Effects of an external magnetic field (B) on the SO₂ fluorescence have been examined under excitation of the ‘C’ band and the single rotational levels of the ‘B’ and ‘E’ bands of the A(¹A₂) ← X¹A₁ transition. For the ‘C’ band, the total SO₂ fluorescence was studied, while for excitation of the single rotational levels, fluorescence of the single rotational lines of (^rR₅(5) (31711 cm^-1), ^pP₇(7) (31662 cm^-1)) (‘E’ band) and of (^rR₈(8) (31000 cm^-1), ^pP₁₀(10) (30927 cm^-1)) (‘B’ band) was studied. Decay of the SO² fluorescence was studied with nanosecond time resolution in the 1?5–50 mTorr region. In the presence of a magnetic field, decay of the total SO₂ fluorescence and of the fluorescence belonging to the single rotational lines were fitted by the bi-exponential functions. In the case of the total SO₂ fluorescence, this function also includes the time independent term, which, however, is dependent on a magnetic field. The time independent term belongs to the long-living component, which can be approximated by a constant in the time-scale studied. Radiationless processes induced by an external field were directly observed. The magnetic field and pressure dependences of the processes induced by a field were studied under excitation of the SO₂ fluorescence by light of a different wavelength. The data obtained were explained by the direct mechanism.