共查询到20条相似文献,搜索用时 15 毫秒
1.
J.W.-H. Leung 《Journal of Molecular Spectroscopy》2005,229(1):108-114
The absorption spectrum of the (2, 0) and (2, 1) bands of the B2Σ+-X2Σ+ transition of YO between 442 and 478 nm were recorded using laser vaporization/reaction with free-jet expansion and cavity ring down laser absorption spectroscopy. Local rotational perturbations have been found for both spin components of the v = 2 level of the B2Σ+ state. The observed perturbations could be ascribed to a degenerate perturbing state interacting with the B2Σ+ state. Least-squares fit of the observed upper state term values yielded molecular constants for the v = 2 level of the B2Σ+ state and the perturbing 2Π state. Earlier ab initio calculations [J. Chem. Phys. 89 (1988) 2160] indicated that the C2Π state is nearby, it is plausible that the C2Π state is the perturbing state. 相似文献
2.
The spectrum of B2Σ+-X2Σ+ system of AlO has been recorded on BOMEM DA8 Fourier transform spectrometer at an apodized resolution of 0.05 cm−1. Nineteen bands of the Δv = 1, 0, −1, and −2 sequences of this band system have been analyzed for the rotational structure. Out of which seven bands, viz. 3-2, 4-3, 2-3, 3-4, 4-5, 5-6 and 6-7 have been analyzed for the first time. The rotational lines of these 19 bands along with 20 earlier analyzed bands, a total of 7200 lines, have been fitted in a simultaneous least squares fit. The study has resulted in determining more precise vibrational and rotational constants of the two states. Because of the high resolution employed it became necessary to invoke H0 and H1 coefficients, and a fifth order term to explain the anomalous spin-doubling observed in the v″ = 5, 6 and 7 levels of the X2Σ+ state. 相似文献
3.
R.R. Reddy Y. Nazeer Ahammed D. Baba Basha K. Narasimhulu L. Siva Sankar Reddy K. Rama Gopal 《Journal of Quantitative Spectroscopy & Radiative Transfer》2006,97(3):344-353
In recent years, high-resolution photoelectron spectroscopy and ab initio calculations have considerably revised and enlarged the understanding of the electronic structure of the NO and NO+ molecules. The experimental potential energy curves for the different electronic states of atmospheric interest molecules like NO and NO+ are constructed by using the Rydberg-Klein-Rees method as modified by Vanderslice et al. The ground state dissociation energies are determined by curve fitting technique using the five parameter Hulburt-Hirschfelder (H-H) function. The estimated dissociation energies are 6.381 and 10.693 eV for NO and NO+, respectively. These values are in good agreement with the literature values. The r-centroids and Franck-Condon factors (FC Factors) for the band system of B2Πr-X2Π of NO and a3Σ+-X1Σ+, A1Π-X1Σ+ of NO+ molecules have been calculated employing an approximate analytical methods of Jarmain and Fraser, and Nicholls and Jarmain. The absence of the bands in these systems is explained. 相似文献
4.
The emission spectrum of the B2Σ+-X2Σ+ system of CN has been observed at high-resolution using a Fourier transform spectrometer. The rotational structure of a large number of bands involving vibrational levels v = 0-15 of both electronic states has been analyzed, and improved spectroscopic constants have been determined by combining the microwave and infrared measurements from previous studies. Improved spectroscopic constants for vibrational levels up to v″ = 18 in the X2Σ+ state and v′ = 19 in the B2Σ+ state have been determined by combining the measurements of the 16-13, 18-17, 18-18, 19-15, and 19-18 bands of Douglas and Routly [Astrophys. J. Suppl. 1 (1955) 295-318] and 17-14 and 17-16 bands of Ito et al. [J. Chem. Phys. 96 (1992) 4195] with our data. The band constants obtained have been used to estimate equilibrium ground state constants for CN. 相似文献
5.
Sixteen emission bands of the B3Π(0+) → X1Σ+ systems of 79BrF and 81BrF have been analyzed rotationally. Measured line frequencies are fitted by least-squares to determine the rotational constants and origin for each band. The least-squares results for 0 ≤ v′ ≤ 4 and 4 ≤ v″ ≤ 12 are merged with constants from previously reported B ← X absorption and X-state microwave data. RKR potentials for the two states and Franck-Condon factors and r-centroids for the BrF (B-X) system are reported. 相似文献
6.
Shaohua Zhang 《Journal of Molecular Spectroscopy》2008,252(1):77-80
The laser-induced fluorescence excitation spectra of jet-cooled CuS molecules have been recorded in the energy range of 17 200-19 500 cm−1. Fourteen observed vibronic bands have been assigned as three transition progressions: A2Σ− (v′ = 0-4)-X2Π3/2 (v″ = 0), A2Σ− (v′ = 0-4)-X2Π3/2 (v″ = 1), and A2Σ− (v′ = 0-3)-X2Π1/2 (v″ = 0). Spectroscopic constants of both the X2Π ground state and the A2Σ− excited state of 63CuS and 65CuS were determined by analyzing their rotationally resolved spectra. Furthermore, the lifetimes of most observed bands were measured for the first time. 相似文献
7.
High resolution infrared emission spectra of ZnH, ZnD, CdH, and CdD have been recorded with a Fourier transform spectrometer. The v = 1 → 0 and v = 2 → 1 bands of ZnH, ZnD, CdH, and CdD, as well as the v = 3 → 2 band of ZnD were observed for the X2Σ+ ground electronic state. In addition, new rotational spectra have been recorded for CdH and CdD using a tunable far-infrared spectrometer, and pure rotational transitions in the v = 1 level of the ground state were measured. The new data were combined with the previous data from diode laser infrared spectra and pure rotation spectra of ZnH/ZnD and CdH/CdD available in the literature. The data from all isotopologues were fitted together using a Dunham-type energy level expression for 2Σ+ states, and Born-Oppenheimer breakdown correction parameters were obtained. The equilibrium rotational constants (Be) of 64ZnH, 64ZnD, 114CdH, and 114CdD were determined to be 6.691332(17), 3.402156(7), 5.447074(18), and 2.750761(6) cm−1, respectively, and the associated equilibrium internuclear distances (re) are 1.593478(2), 1.593001(2), 1.760098(3), and 1.759695(2) Å, respectively. Simple reduced mass scaling for the spin-rotation interaction constants of ZnH and CdH fully accounted for their isotopologue dependence, and no Born-Oppenheimer breakdown correction was required for these parameters. 相似文献
8.
The electronic emission spectrum of the A3Π0-X1Σ+ and B3Π1-X1Σ+ transitions of Gallium monochloride molecule (69GaCl) has been recorded on BOMEM DA8 Fourier transform spectrometer at an apodized resolution of 0.035 cm−1. The rotational structure of the 0-0, 1-0, 2-1, and 3-2, bands belonging to A-X and 0-0, 0-1, 1-2, and 0-2 bands belonging to B-X transitions has been analyzed and equilibrium rotational constants for the X1Σ+ and A3Π0 states have been obtained. For the first time we are able to determine the Λ-doubling constants in the v = 0 and 1 levels of the B3Π1 state. 相似文献
9.
Iouli E. Gordon Alireza Shayesteh Peter F. Bernath 《Journal of Molecular Spectroscopy》2005,229(1):145-149
Fourier transform infrared emission spectra of MnH and MnD were observed in the ground X7Σ+ electronic state. The vibration-rotation bands from v = 1 → 0 to v = 3 → 2 for MnH and from v = 1 → 0 to v = 4 → 3 for MnD were recorded at an instrumental resolution of 0.0085 cm−1. Spectroscopic constants were determined for each vibrational level and equilibrium constants were found from a Dunham-type fit. The equilibrium vibrational constant (ωe) for MnH was found to be 1546.84518(65) cm−1, the equilibrium rotational constant (Be) is 5.6856789(103) cm−1 and the eqilibrium bond distance (re) was determined to be 1.7308601(47) Å. 相似文献
10.
The emission spectra of the A2П-X2Σ+ (red) system of 12C14N have been reinvestigated in the 3500-22 000 cm−1 region at high resolution using a Fourier transform spectrometer. In total, spectra of 63 bands involving vibrational levels up to v′ = 22 of the A2П state and v″ = 12 of the X2Σ+ ground state have been measured and rotationally analyzed providing an improved set of spectroscopic constants. The present measurements of the Δv = −2 sequence bands of 12C14N and those of 13C14N from Ram et al. (2010) [36] allow for a much improved identification of these two isotopologues in the near infrared spectra of carbon stars. 相似文献
11.
Emission spectra of the A2Π3/2-X2Σ+ (0, 1), (0, 0), and (1, 0) bands and the B2Σ+-X2Σ+ (0, 1), (0, 0), (1, 0), (2, 0), and (3, 1) bands of ScS have been recorded in the 10 000-13 500 cm−1 region at a resolution of 0.05 cm−1 using a Fourier transform (FT) spectrometer. The A2Πr-X2Σ+ (1, 0) band as well as the B2Σ+-X2Σ+ (0, 0) and (1, 0) bands have been recorded at high resolution (±0.001 cm−1) by laser excitation spectroscopy using a supersonic molecular beam source. The FT spectral features range up to N = 148, while those recorded with the laser cover the “low-N” regions. The lines recorded with the laser exhibit splittings due to the 45Sc (I = 7/2) magnetic hyperfine interactions, which are large (∼6.65 GHz) in the X2Σ+ state and much smaller in the B2Σ+ and A2Π states. The energy levels were modeled using a traditional ‘effective’ Hamiltonian approach, and improved spectroscopic constants were extracted and compared with previous determinations and theoretical predictions. 相似文献
12.
Time-resolved Fourier transform emission spectroscopy of AΠ-XΣ infrared transition of the CN radical
The A2Π-X2Σ+Δv = −3 bands of the 12C14N radical have been observed by time-resolved Fourier transform spectroscopy in the 1850-3100 cm−1 region with a wavenumber resolution of 0.025 cm−1. The radical was produced in a pulsed positive column discharge in a cyanogene and helium mixture. Seven bands of v = 0-3, 1-4, 2-5, 3-6, 4-7, 5-8, and 6-9 were analyzed to give the molecular constants of each state by least-squares fitting of 801 lines. The pulsed discharge was found to be efficient for production of CN in the excited A2Π state. The vibrational excitation temperature was determined to be 6680 ± 835 K and 6757 ± 534 K for the A2Π and X2Σ+ states, respectively. The population of the A2Π was found to be 4% of that of the X2Σ+ state in the time after turning off the discharge. 相似文献
13.
Anup Pramanik 《Journal of Molecular Spectroscopy》2007,244(1):13-23
Electronic structure and spectroscopic properties of the low-lying electronic states of the SiC radical have been determined from the ab initio based configuration interaction calculations. Potential energy curves of 32 Λ-S states of singlet, triplet, and quintet spin multiplicities have been constructed. Spectroscopic constants (re, Te, and ωe) of 23 states within 6 eV are reported and compared with the existing data. The dipole moments (μe) of most of these states at their respective equilibrium bond lengths have been computed. Effects of the spin-orbit coupling on the spectroscopic properties of SiC have been studied. The E3Π state is found to be an important one which has not been studied before. A transition of the type E3Π-X3Π is predicted to take place in the range 25 000-26 000 cm−1. The partial radiative lifetimes for several electric dipole allowed transitions such as A3Σ+-X3Π, B3Σ+-X3Π, C3Π-X3Π, D3Δ-X3Π, E3Π-X3Π etc. have been reported. 相似文献
14.
J. Borkowska-Burnecka W. ?yrnicki E.H. Fink 《Journal of Quantitative Spectroscopy & Radiative Transfer》2008,109(9):1599-1606
Rotational and vibrational temperatures of electronically excited BiN radicals in a low-pressure Bix+N/N2*/N2+Ar chemiluminescent flame have been deduced from high-resolution Fourier-transform emission spectra. Bands of three electronic transitions, a3Σ+(a11)→X1Σ+(X0+), b5Σ+(b10+)→X1Σ+(X0+), and b5Σ+(b10+)→a 3Σ+(a11), were analysed to determine the optical temperatures in the a3Σ+(a11) and b5Σ+(b10+) states. The rotational temperatures characterising the rotational populations in the a11, v=0 and 1 states were determined from the a1→X, 0-2, 0-3, 0-4, 1-1, and 1-2 bands. The b1→X, 0-8 and 0-11 bands, and the b1→a1, 0-0 bands served to determine the rotational temperature of the radicals in the b10+, v=0 state. The temperatures derived from the various bands and transitions were well consistent and the mean rotational temperature was determined to be 353±18 K, which is close to the translational temperature of the gas.Vibrational temperatures of the radicals in the a11 and b10+ states were derived from band intensities of the a1→X and from the b1→X as well as b1→a1 systems, respectively. The Franck-Condon factors needed were calculated with RKR potentials deduced from literature values of the rotational and vibrational constants in the three states involved. The a11 vibrational temperature (336±21 K) was close to the rotational temperature, while the b10+ vibrational temperature (438±36 K) differed, likely due to the previously observed perturbation of the b10+ state. 相似文献
15.
The emission spectra of CaH and CaD have been recorded at high resolution using a Fourier transform spectrometer and bands belonging to the E2Π-X2Σ+ transition have been measured in the 20 100-20 700 cm−1 region. A rotational analysis of 0-0 and 1-1 bands of both the isotopologues has been carried out. The present measurements have been combined with the previously available pure rotation and vibration-rotation data to provide improved spectroscopic constants for the E2Π state. The constants ΔG(½) = 1199.8867(34) cm−1, Be = 4.345032(49) cm−1, αe = 0.122115(92) cm−1, re = 1.986633(11) Å for CaH, and ΔG(½)=868.7438(46) cm−1, Be = 2.212496(51) cm−1, αe = 0.036509(97) cm−1, re = 1.993396(23) Å for CaD have been determined. 相似文献
16.
The emission spectrum of the B3Π1-X1Σ+ band-system of the InCl molecule has been recorded on a Fourier transform spectrometer at an apodized resolution of 0.025 cm−1. The rotational structure of 1-0, 2-1, 0-0, 0-1, 1-2, 0-2, and 1-3 bands belonging to the B3Π1-X1Σ+ transition of In35Cl has been analyzed and accurate equilibrium rotational constants of the B3Π1 state, have been obtained. Precise Λ-doubling constants of the B3Π1 state (v=0, 1, and 2) are also reported for the first time. 相似文献
17.
Twenty-five bands of the B2Σ → X2Σ system of AlO with 0 ≤ v′ ≤ 9 and 0 ≤ v″ ≤ 6 have been photographed at high resolution. The measured positions of the assigned lines of each band have been fitted by least-squares to obtain estimates of the constants (B′, D′, B″, D″), the band origin, and Δγv′,v″, which is the difference of the upper and lower state spin-doubling constants (γ′v and γ″v). The parameters from individual bands have been merged to single-valued estimates, as well as to polynomial representations in (). Although the spin-doubling constants are not found absolutely for either state, their vibrational dependences are well determined. The data are employed in the computation of RKR potential energy curves and an array of Franck-Condon factors and r-centroids. 相似文献
18.
A combined analysis of the A2Πi → X2Σ+ and B2Σ+ → X2Σ+ band systems of AlO, involving 21,500 line assignments, has been performed. The analysis indicates that the previously reported γ values of the B2Σ+ state are questionable. The present analysis shows that γ(B2Σ+) ≈ 0.014 cm−1, essentially independent of the vibrational level. The positive sign is consistent with second order interaction with the higher-lying C2Πr and lower-lying A2Πi states. It also appears that many of the previously reported γ and γD values of X2Σ+ (v > 0) are doubtful. In fact, γ(X2Σ+) is observed to become increasingly negative for v″ > 1, due to second order interaction with the low-lying A2Πi state. The present results are based on models where the hyperfine structure of the 2Σ+ states has been taken into account explicitly. Intensity patterns of the branches of the B2Σ+ → X2Σ+ system have been shown to be influenced by the case bβS coupling in the ground state v = 0,1 levels. This gives rise to intensity differences of around 10 percent in the R1/R2 and P1/P2 doublet components. The synthesized intensity patterns are fully in accord with the F1/F2 assignments of the present work. 相似文献
19.
In the electronic emission spectrum of the 12C16O+ molecule, 11 bands of the Comet-Tail (A2Πi-X2Σ+) system have been recorded and analyzed. Spin splitting in most of the observed lines of the 0-2, 1-0, 2-0, 2-1, 3-0, 4-0, 4-2, 6-0, 7-0, 7-1, and 8-1 bands, comprising nearly 3400 lines, has been recorded under high resolution by conventional spectroscopy. The rotational analysis of bands has been performed by nonlinear least-squares procedures and by means of effective Hamiltonians of Brown et al. and the rovibronic structure parameters have been obtained. The data of bands of the A-X system and earlier analyzed bands of the B-X and B-A systems have been merged together. As a result of this global fit, the state of information about the energy structure has been significantly enlarged for the A state and enlarged and improved for the X state. Also RKR potential curves for both states and Franck-Condon factors as well as r-centroids of the Comet-Tail system of CO+ have been calculated. 相似文献
20.
J. A. Coxon 《Journal of Molecular Spectroscopy》1974,50(1-3)
24 bands of the B3Π(0+) ← X1Σ+ system of 79Br35Cl and 81Br35Cl have been photographed at high resolution. Direct least-mean square fits of the measured line frequencies were made to determine band origins and rotational constants in the ranges 1 ≤ v″ ≤ 7, 2 ≤ v′ ≤ 8. A reiterative procedure was adopted in which the higher order centrifugal distortion constants (Dv, Hv) were constrained to theoretical values calculated from RKR potential curves. The results of the analysis are used to obtain a set of Franck-Condon factors and r-centroids for the B-X system of BrCl. 相似文献