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1.
D.L. Albritton W.J. Harrop A.L. Schmeltekopf R.N. Zare 《Journal of Molecular Spectroscopy》1973,46(1):103-118
The discrepancies concerning the optical and microwave values of B0 and D0 for the X state of O2 have been removed by a nonlinear least-squares fit to all of the lines of the O2, Red Atmospheric bands recorded by Babcock and Herzberg (Astrophys. J., 108, 167, 1948). The resulting values for B0″ and D0″ are in excellent agreement with the Raman and microwave values. Improved values are determined for B1″, D1″, γ1″ (spin-rotation), and ?1″ (spin-spin). Both γv″ and ?v″ increase in magnitude from v″ = 0 to v″ = 1. Improved Dunham Yi0 and Yi1 expansion coefficients are determined for the state, from which the Rydberg-Klein-Rees potential is constructed. 相似文献
2.
D.L Albritton W.J Harrop A.L Schmeltekopf R.N Zare 《Journal of Molecular Spectroscopy》1973,46(1):89-102
Existing high-resolution data for the Second Negative band system have been analyzed using a nonlinear least-squares fit that employs numerically diagonalized Hamiltonians. Values for the full set of molecular constants of the A2Πu and X2Πg states are obtained for the first time. In addition to values for ν0(v′, v″), Bv, and Dv, the values for the spin-orbit coupling constants Av are determined for both states. For the X2Πg state, which is near Hund's case (a), the agreement between these Av″ values and those predicted by theory is good. However, for the A2Πu state, which is much nearer to case (b), these Av′ values and theory disagree both in magnitude and in variation with vibrational level. The A2Πu state is an inverted state for vibrational levels v′ ≤ 5 and is a regular state for levels v′ = 6–8 (the upper limit of present high-resolution data). Λ-doubling parameters are determined for the X2Πg state, the only state where Λ-doubling is statistically significant. Spin-rotation interaction is not statistically significant for either state. Dunham Yi0 and Yi1 expansion coefficients are determined for each state. Theoretical Dv values calculated from RKR potentials are used to improve the Bv values in the reduction of the data. 相似文献
3.
J.A. Coxon 《Journal of Molecular Spectroscopy》1980,82(2):264-282
Literature data for the line frequencies of the B3Π(0u+) ← X1Σg+ transition of Cl2 are fitted directly by least squares to obtain new molecular constants. The constants from individual bands are merged to obtain single-valued estimates of the rotational constants for each vibrational level of the B state. The results are combined with recent data from the B → X system in emission to obtain new RKR turning points for the B and X states, and Franck-Condon factors for the B-X system. The new constants are also used to provide revised long-range parameters for Cl2(B) which differ from those of earlier work. In particular, the coefficient C5 of the leading term in the inverse-power long-range potential is now found to be . Theoretical results for the variation of centrifugal distortion parameters for levels near dissociation are tested for Dv and Hv, and an extrapolation based on this behavior is used to facilitate determination of reliable Bv and G(v) values for the highest observed B-state levels. 相似文献
4.
A theoretical model used to describe the and B3Πg states of N2 is presented. Using recently acquired high resolution spectra of the (0-0) band, rotational energy levels of the v = 0 vibrational levels of these two states are generated with this model. These levels are in excellent agreement with those obtained using a combination differences technique. The precision of the model generated levels is 0.01 cm?1. The previously unpublished rotational levels of Dieke and Heath for the , B3Πg and C3Πu states are referenced to the (v = 0, J = 0) ground level and tabulated here. Estimates of the precision of their work are made. 相似文献
5.
Paul S. Julienne 《Journal of Molecular Spectroscopy》1973,48(3):508-529
The Kolos-Wolniewicz potentials for the H2 and C1Πu states were used together with the hypothesis of pure precession for the rotation-electronic interaction, to calculate the nonadiabatic energy levels of these states for J = 1 to 5. The complete coupling matrix was computed using accurate numerical vibrational wavefunctions. The calculated Λ-doubling of the v = 0 to 12 C vibrational levels generally agrees well with experimental values, and the nonadiabatic shifts in the B rotational constants qualitatively explain the difference between the theoretical and RKR potentials for this state.The interaction of the B′ and D1Πu states was also investigated, but only qualitatively since adiabatic potentials of sufficient accuracy do not exist for these states. The Λ-doubling of the Dv = 0 rotational levels agrees well with the experimental values. An appreciable “background” nonadiabatic shift in the B′ rotational constants was found. This shift, which is nearly 5 percent of Bv, is in addition to that of strong local two-level interactions and was not “deperturbed” in constructing the B′ RKR potential. The result is that the RKR turning points differ by about 0.04 au from the “true” adiabatic turning points. This conclusion is supported by a Hartree-Fock calculation of the B′ potential to the left of Re. 相似文献
6.
Two band groups near 1450 Å, first observed by Tanaka, Yoshino, and Freeman (J. Chem. Phys.62, 4484–4496 (1975)) in discharges through mixtures of helium and argon and assigned by them to the HeAr+ ion, were studied under high resolution. Like the similar spectrum of HeNe+ previously investigated, the spectrum of HeAr+ is a charge transfer spectrum. The upper state B2Σ+ of both band groups is derived from while the two lower states and X2Σ+ are derived from . All three states are very weakly bound, the two lower states even more weakly than the upper state. Unlike HeNe+ most of the HeAr+ bands are violet shaded. In the longward band group each band shows only three branches while in the shortward group there are four. The former observation shows that the state behaves like a 2Σ? state with γv ≈ 0. The B, D, γ, p, and ΔG values of all states were evaluated. While the Bv values of upper and lower states are nearly equal, the Dv values are quite different and this difference accounts for the violet shading of most of the bands even when B′v is slightly smaller than B″v; it also accounts for some of the extraheads and linelike features in the rotational structure. As in HeNe+ the component of 2Π was not observed. 相似文献
7.
Takashi Ishiwata Atsuto Tokunaga Tsutomu Shinzawa Ikuzo Tanaka 《Journal of Molecular Spectroscopy》1984,108(2):314-327
An optical-optical double-resonance technique has been applied to study the D(0u+) ion-pair state of Br2 in a one-photon resonant three-photon absorption. The OODR transition proceeds through the high vibrational level of the B3Π(0u+) state, which compromises a large Franck-Condon shift required for the excitation of Br2 from the X1Σg+ state to the D(0u+) state. Dunham parameters of the D(0u+) state, based on a global least-squares fit of 407 transitions (v′ = 0–16, J′ = 17–115), are Y00 = 49928.443(41), Y10 = 134.467(19), Y20 = ?8.71(27) × 10?2, Y30 = ?3.36(10) × 10?3, Y01 = 4.2382(15) × 10?2, Y11 = ?1.061(36) × 10?4, Y21 = ?2.00(27) × 10?6, and Y02 = ?1.93(11) × 10?8 for 79Br2 (all in cm?1, and 3σ in parentheses). The single rovibronic fluorescence spectrum of the D(0u+) state shows a transition terminating on the X1Σg+ ground state, and establishes the absolute v′ numbering on the basis of the Franck-Condon factor calculations. The v′ = 2 and 3 levels of the D(0u+) state are strongly perturbed due to the heterogeneous interaction with the 1u state correlating with the same ionic products of the D(0u+) state at the dissociation limit, . 相似文献
8.
P.F. Bernath B. Pinchemel R.W. Field K. Möller T. Törring 《Journal of Molecular Spectroscopy》1981,88(2):420-423
Adiabatic corrections to the Born-Oppenheimer potential energy curve for the state of the hydrogen molecule has been computed using a 60-term variational wavefunction in the form of an expansion in elliptic coordinates and depending explicitly on the interelectronic distance. For three internuclear separations new Born-Oppenheimer energies are also given which represent corrections of the previously published values. For H2 the adiabatic correction to the dissociation energy amounts to 57.5 cm?1. The computed dissociation energies for H2, HD, and D2 are by 23–25 cm?1 smaller than the experimental values, the discrepancy being probably due to the convergence error of the Born-Oppenheimer potential. A few lowest vibrational levels and vibrational quanta have been calculated for H2, HD and D2, and compared with the experimental results. 相似文献
9.
Molecular beam electric resonance spectroscopy has been used to measure the l-type doubling transitions in carbonyl sulfide. Transitions in J = 4 to J = 20 have been observed for the (0220) vibrational state and for J = 1 and J = 2 for the (0310) state. The data has been analyzed to give the v = 2 energy separation , and the vibrational dependence of q to be 86.52(9)(v2 + 1) KHz. The dipole moment of the (0220) vibrational state is 0.6936(3) D. 相似文献
10.
Turning points of the vibrating SiS molecule in the D1Π and X1Σ+ electronic states are evaluated using R-K-R-V method. Franck-Condon (FC) factors and r-centroids are computed for the transition of the molecule using wavefunctions appropriate to R-K-R-V potential energy curves. The results of the FC-factors vary in accordance with the estimated intensities and also satisfy the vibrational sum rule. The sequence difference Δr remains approximately constant in the computed r-centroids. 相似文献
11.
Two band systems of PCl, A3Πr → X3Σ? and b1Σ+ → X3Σ?, have been observed from the reaction of with PCl3 at pressures of 1–2 Torr. Seventy-eight bands of P35Cl and 31 bands of P37Cl in the region 4000–6000 Å have been assigned to the A3Πr → X3Σ? system and include levels with v′ = 0, 1, 2 and v″ = 3–18. The ground state numbering was obtained from a study of the vibrational isotope effect. The (0,0) sequence of the b1Σ+ → X3Σ? system occurs near 8200 Å and has been observed up to v′ = 10. Vibrational constants for all three states are derived from least-squares fits of the measured bandhead wavenumbers. The A ← X absorption system of PCl reported by Basco and Yee in flash photolysis of PCl3 was not observed, and is probably due to absorption to a Rydberg state of PCl. 相似文献
12.
The emission spectrum of HCl+ has been measured and analyzed for four isotopic combinations. These analyses extend previous work and provide rotational constants for the v = 0–2 levels of the ground state and for the v = 0–9 levels of the excited state. RKR potentials have been determined for both states, although the upper state could not be fitted precisely to such a model. Calculated relative intensities based on these potentials demonstrated that the electronic transition moment must change rapidly with lower state vibrational quantum number. Although considerable caution should be exercised in applying the concept of equilibrium constants to the state, the following are the best estimates of these constants (in cm?1) for the state of H35Cl+: Be = 9.9406, ωe = 2673.7, Ae = ? 643.7, and . For the state of H35Cl: Te = 28 628.08, Be ~ 7.505, ωe ~ 1606.5, and . 相似文献
13.
New spectrograms of CO below 1200 Å reveal that emission bands terminating on the high energy and 1Π states plus most of the previously reported unidentified emission bands of CO actually originate from molecular nitrogen. Four new emission band systems in CO, tentatively identified as V1Π-X1Σ+, W1Π-X1Σ+, Y1Σ+-X1Σ+, and Z1Σ+-X1Σ+, have been observed. The corresponding Tv0′s are 98917, 102804, 99963, and 105724 cm?1, respectively. 相似文献
14.
Paul S. Julienne 《Journal of Molecular Spectroscopy》1976,63(1):60-79
The role of spin-orbit mixing in the O2 Schumann-Runge predissociation is investigated. The state is found to cross the state near 2.0 Å with an interaction matrix element of approximately 55 cm?1. This state contributes to the widths of the Bv ≥ 6 levels, but introduces only small level shift perturbations. When the partial widths due to the interaction are added to the previously calculated widths due to the 5Πu, 3Πu, and 1Πu states, reasonable agreement is obtained with experimental measurements on O16O16 and O18O18. The possibility of non-Lorentzian line profiles and the dependence of the width on rotational quantum number is investigated. The approximation of the spin-orbit matrix element by its value at the crossing point is shown to be a good approximation for calculating the second difference perturbations. 相似文献
15.
Discharges through mixtures of helium and neon show two band groups near 4250 and 4100 Å as first observed by Druyvesteyn. These bands, assigned to the HeNe+ ion by Tanaka, Yoshino, and Freeman, have been studied under high resolution and have been fairly completely analyzed. The upper state of the transition is a very weakly bound state resulting from . There are two lower states resulting from the two components of . The upper of these two () is also very weakly bound while the lower of the two, the 2Σ+ ground state, has a dissociation energy of 0.69 eV and an re value of 1.30 Å. All bands in both band groups show four branches designated Rff, Qef, Qfe, and Pee. From their analysis the rotational constants in the various vibrational levels of the three electronic states have been determined. While no spin splitting in the B2Σ+ state has been found the ground state X2Σ shows a very large spin splitting and the state a very large doubling. The vibrational numberings in all these states were established by the study of the spectrum of 3HeNe+. At the same time the hyperfine structure observed in all lines of 3HeNe+ confirmed the nature of the upper state B2Σ+ as resulting from He+ + Ne, i.e., by charge exchange from the ground state. The component of the 2Π state has not been observed, presumably because of low intensity. 相似文献
16.
The emission spectrum of the He2 molecule has been rephotographed in the ~4000–~5700 Å region and the , , and transitions analyzed. The 4dδj3Δu, 4dπj3Πu, and states have been characterized through v = 2 and the 4dδJ1Δu, 4dπJ1Πu, , and states for v = 0. The term levels for these perturbed and l-uncoupled states have been confirmed (a) by analyses of bands with common levels from Δv = 0, ±1 sequences and (b) by analyses of the transitions between the above states from 4d and 4s and the and states associated with 3pσ. Molecular constants are reported which have been partially corrected for the effects of l-uncoupling and the homogeneous perturbations between the state pairs J, H and j, h. 相似文献
17.
The molecular-beam, laser-rf, double-resonance technique has been used to make high-precision measurements of both the v and N dependences of the spin-rotational and hyperfine splittings in the ground state of CaF. The precision (1 ppm) and scope (1 ≤ N″ ≤ 119, 0 ≤ v″ ≤ 4) of the data allow evaluation of many of the parameters (with the Dunham expansion) in the Hamiltonian. The results are compared with new ab initio calculations. 相似文献
18.
Laser-induced fluorescence excitation has been used to measure Stark splittings of selected lines in the and band systems of H2CS in electric fields up to 13 kV/cm. The derived excited state a-axis dipole moments are 0.820 ± 0.007 D for the 41 level of the 1A2 state; 0.838 ± 0.008 D for the zeroth vibrational level of 1A2; and 0.534 ± 0.015 D for the zeroth vibrational level of the 3A2 state. These results are compared with the corresponding values of H2CO, and interpreted in terms of the changing localization of the π and orbitals accompanying electronic excitation. 相似文献
19.
L.E. Brus 《Journal of Molecular Spectroscopy》1979,75(2):245-250
Previously unobserved acetylene fluorescence occurs following 1933-Å ArF laser excitation of C2H2 or C2H4 and their deuterated analogs in solid Ne and Ar hosts at 4.2 K. Acetylene is a photolysis product of matrix-isolated ethylene. Ground-state vibrational levels as high as ν″3 = 30 of the degenerate ν3 bending vibration are observed for C2D2. Only ν3 is appreciably active in the fluorescence. The negative ν3 anharmonicity, previously observed in the gas phase, also occurs in Ne host. Consideration of rotational selection rules indicates that the Ne host strongly hinders free rotation about the low-moment-of-inertia axis in the excited state. 相似文献
20.
Keiji Matsumura Kentarou Kawaguchi Keiichi Nagai Chikashi Yamada Eizi Hirota 《Journal of Molecular Spectroscopy》1980,84(1):68-73
The v = 1 ← 0 vibration-rotation bands of the NS radical in the and electronic states were observed by using a tunable diode laser. From the least-squares analysis the band origins were determined to be 1204.2755(12) and 1204.0892(19) cm?1, respectively, for and . The rotational and centrifugal distortion constants and the internuclear distance in the X2Π electronic state were obtained as follows: Be = 0.775549(10) cm?1, De = 0.00000129(33) cm?1, and , with three standard deviations indicated in parentheses. 相似文献