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1.
Two new systems of emission bands near 2100 and 3100 Å have been produced by a microwave discharge in B2S3 vapor. From the known X2Σ+ and A2Πi states of BS, these systems have been assigned as E2Σ+ → X2Σ+ and E2Σ+ → A2Πi. Constants in cm?1 for the new state are , 相似文献
2.
In the same spirit in which Benjamin, Bona, and Mahoney modified the Korteweg-de Vries equation (Ux+Ut+UUx+Uxxx=0) to obtain the so-called BBM equation, Ux+Ut+UUx?Uxxt=0, we propose a different modification: Ux+Ut+UUx+Uxtt=0. The advantages in this equation are 1) the system is conservative since it can be derived from the Lagrangian density for large wave-numbers |k|, the infinitesimal-wave phase speed falls off like , in accord with physical intuition; 3) since the equation is of second order in t, both U and Ut can be independently specified for t = 0. Several conservation laws satisfied by solutions to this equation are given. 相似文献
3.
G.C. Salzman Gerald G. Ohlsen J.C. Martin J.J. Jarmer T.R. Donoghue 《Nuclear Physics A》1974,222(3):512-524
Angular distributions of six polarization transfer coefficients ; of the four analyzing powers Ay(θ), Axx(θ), Ayy(θ), and Azz(θ); and of the polarization function Pý(θ), have been measured atEd = 10.00 MeV for the reaction 2H(d, n)3He. Measurements were made for neutron lab angles between 0° and 80° in 10° steps. Additionally the y-axis associated quantities were measured at θ1ab = 99°. Most of the measured coefficients are large at some angles and all show considerable variation with angle. 相似文献
4.
Harry Partridge Charles W. Bauschlicher James R. Stallcop 《Journal of Quantitative Spectroscopy & Radiative Transfer》1985,33(6):653-655
Potential energy curves for the , and states of N+2 that dissociate to N () and , have been determined from a complete active space self-consistent field calculation. The state is found to be significantly bound (De = 2.68 eV) with a minimum at 1.72 Å. 相似文献
5.
Robert S. Mulliken 《Journal of Molecular Spectroscopy》1976,61(1):92-99
Predissociations in the y1Πg and Rydberg states of N2 (configurations and , respectively) and their likely causes, are discussed. Peaking of rotational intensity at unusually low J values, without sharp breaking off, is interpreted as due to case c? or case ci predissociation. Λ doubling in the y state, attributed to interactions with the state and with another, 1Σ+, state of the same electron configuration as x, is analyzed. From this analysis the location of the (unobserved) state, here labeled x′, is obtained. It is concluded that the predissociation in the Π+ levels of the y state is an indirect one mediated by the interaction with x′ coupled with predissociation of x′ by a state dissociating to atoms: combined, however, with perturbation of the y state by the k1Πg Rydberg state (configuration ), whose Π+ levels are completely predissociated. 相似文献
6.
Harry Donald Brooke Jenkins Kenneth Frank Pratt 《Journal of Physics and Chemistry of Solids》1977,38(6):573-579
The opportunity to test a new equation for the computation of the lattice energy and at the same time examine a disparity in the literature data for the enthalpy of formation of the azide ion, was the motivation for this study. The results confirm our earlier calculation and show the new equation to be reliable. Thermodynamic data produced in the study take values: ΔHθhyd(N3?) = ?315 KJ mol?1 or ΔHθhyd(N3?) = ?295 KJ mol?1UPOT(NaN3) = 732 kJ mol?1UPOT(KN3) = 659 kJ mol?1UPOT(RbN3) = 637 kJ mol?1UPOT(CsN3) = 612 kJ mol?1UPOT(TIN3) = 689 kJ mol?1. The lattice energies of azides whose enthalpies of formation are documented have been calculated as well as the enthalpy of formation of the azide radical. 相似文献
7.
The hard photon emission in e+e? → μ+μ?γ is investigated to order α3. Formulas for a number of distributions are obtained, when neglecting terms of order (me/?)2 and (mμ/?)2. Both charge-even and charge-odd contributions are calculated. The total contribution to the charge asymmetry parameter does not exceed 5% for the c.m.s. energy 2? = 3 GeV. 相似文献
8.
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
9.
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
10.
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
11.
The influence of self-fields on the equilibrium and stability properties of relativistic beam-plasma systems is studied within the framework of the Vlasov-Maxwell equations. The analysis is carried out in linear geometry, where the relativistic electron beam propagates through a background plasma (assumed nonrelativistic) along a uniform guide field , It is assumed that for the beam electrons (ν is Budker's parameter, and γ0mc2 is the electron energy), but no a priori assumption is made that the beam density is small (or large) in comparison with the plasma density, or that conditions of charge neutrality or current neutrality prevail in equilibrium. It is shown that the equilibrium self-electric and self-magnetic fields, and , can have a large effect on equilibrium and stability behavior. Equilibrium properties are calculated for beam (j = b) and plasma (j = e, i) distribution functions of the form fb0(H, Pθ, Pz) = F(H ? ωrbPθ) × δ(Pz ? P0)(j = b), and (j = e, i), where H is the energy, Pθ is the canonical angular momentum, Pz is the axial canonical momentum, and ωrj (the angular velocity of mean rotation for j = b, e, i), Vj (the mean axial velocity for j = e, i), and P0 are constants. The linearized Vlasov-Maxwell equations are then used to investigate stability properties in circumstances where the equilibrium densities of the various components (j = b, e, i) are approximately constant. The corresponding electrostatic dispersion relation and ordinary-mode electromagnetic dispersion relation are derived (including self-field effects) for body-wave perturbations localized to the beam interior (r <Rb). These dispersion relations are analyzed in the limit of a cold beam and cold plasma background, to illustrate the basic effect that lack of charge neutrality and/or current neutrality can have on the two-stream and filamentation instabilities. It is shown that relative rotation (induced by self-fields) between the various components (j = b, e, i) can (a) result in modified two-stream instability for propagation nearly perpendicular to , and (b) significantly extend the band of unstable kz-values for axial two-stream instability. Moreover, in circumstances where the beam-plasma system is charge-neutralized but not current-neutralized, it is shown that the azimuthal self-magnetic field has a stabilizing influence on the filamentation instability for ordinary-mode propagation perpendicular to . 相似文献
12.
Although is forbidden in near case c molecules the A′ ← X transition can be efficiently accomplished by the three-step sequence . Transitions to a range of levels of A′, vA′ = 2–38, have been recorded by this means, using J-selective polarization-labeling spectroscopy. Principal constants of the A′ state of I35Cl are Te = 12682.05, ωe = 224.57, ωeχe = 1.882, ωeye = ?0.0107, Be = 0.08653, and αe = 0.000675 cm?1. The A′ state is therefore similar in its physical characteristics to two other (relatively) deep states, and , of the 2431 configuration. 相似文献
13.
The emission spectrum of the He2 molecule has been rephotographed in the ~3200–4100 Å region and the , , and transitions analyzed. The g, k′, and n states, which have not been reported previously, are characterized through v = 1, 2, and 1, respectively. Several small accidental perturbations have been observed in the rotational manifolds of the k′ and n states. 相似文献
14.
The resonant 2-photon E(O+g) ← B(O+g) ← X(O+g) transition of I2 vapor has been studied by polarization spectroscopy, leading to a rotational analysis of the ν = 0–15 vibrational levels of the E state. The principal constants determined are . 相似文献
15.
The radiative corrections of O(α) to the final electron spectrum and the total cross sections for the processes are studied in the framework of the SU(2)L ? U(1) theory. The electroweak corrections to the fisrt two processes are presented in two equivalent schemes in terms of (Gμ, sin2θw) and . As a byproduct, the relationship to O(α) between the basic parameters (defined by modified minimal subtraction) is explicitly given. The QED corrections are evaluated in the extreme relativistic (ER) regime of the final electron (E′e ? me) for the situation in which the bremsstrahlung photons are unobserved and unrestricted. The ER approximation allows us to obtain simple analytic expressions for the differential electron spectrum and the total cross sections. The relationship to O(GFα) between the spin-averaged differential cross sections for the above processes in the ER regime is derived. 相似文献
16.
Emission spectra for the electronic transitions and of He2 are reported and the electronic structures of and characterized. The energy levels associated with exhibit extensive channel mixing, which leads to a breakdown of conventional band models for the higher n1-members of these Rydberg “series.” However, a model based on multichannel quantum defect theory quantitatively correlates the observed level structures. The higher-energy () portions of the channels can be represented by two eigen-quantum defects μ1 = 0.225 and μ2 = 0.930 and the close- to loose-coupling matrix elements and . The inclusion of energy dependence in the μα's leads to quantitative correlations for all n1-values. 相似文献
17.
A frequency tunable infrared source has been constructed by using the (Ar-laser) - (dyelaser) difference frequency method developed by Pine and applied to the observation of the overtone bands of PH3 3ν2 ← 0 and 4ν2 ← ν2 in the 3.4 μm region and 4ν2 ← 0 in the 1.6-μm region. A Stark modulation method was used to increase the sensitivity of detection. For transitions which were well modulated, the minimum detectable absorption coefficient was estimated to be ~3 × 10?7 cm?1 using a 3-m cell. Emphasis was placed on the observation of the A1-A2 splitting for K = 3n rotational levels. For the 3ν2 state splittings were observed for K = 3, 6, and 9 because PH3 is a very nearly spherical top in this state. The magnitude and the J dependence of the observed K = 3n splittings have been analyzed by using a normal symmetric rotor Hamiltonian and a centrifugal distortion term of the form . 相似文献
18.
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
19.
J. Heintze G. Heinzelmann P. Igo-Kemenes R. Mundhenke H. Rieseberg B. Schürlein H.W. Siebert V. Soergel H. Stelzer K.-P. Streit A.H. Walenta 《Nuclear Physics B》1979,149(3):365-380
The decay K+ → e+υγ has been investigated. For the structure-dependent part with positive γ-helicity (SD+) the branching ratio is obtained from 51 ± 3 events observed in the kinematical region Ee ? 235 MeV, Eγ > 48 MeV and θeγ > 140°. For the corresponding part with negative γ-helicity we obtain an upper limit Γ(SD?)/Γ(SD+) < 11 (90% CL) from the sample of electrons with energies 220 MeV ? Ee < 230 MeV and with no γ in the backward direction. This upper limit implies that the ratio of structure-dependent axial vector amplitudes lies outside the region .For the decay the limit 90% confidence level) was found. 相似文献
20.
We calculate the production of narrow resonances with even charge conjugation in e+e? annihilation in the quarkonium and vectordominance models. We give unitarity bounds for in terms of and . The electromagnetic production dominates through the neutral current at low energies independent of details of the model. For masses above 10 GeV the situation is reversed. 相似文献