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1.
Accurate SCF computations are reported on the Rydberg states of N2 of electron configurations , , and ---3σg2πg, also on the valence states of the configuration . The Rydberg state calculations supplement those of Lefebvre-Brion and Moser. A comparison is made between the states and the parallel set of states of the configuration. This comparison shows a sharp difference in the 1Σ+ states of the two configurations, the 1Σ+ state being very high in the latter but relatively low in the former configuration. Recknagel coefficients are given for the several states of the two configurations; as expected, these are much smaller for the configuration. Also, the 1Δ state is relatively lower for the latter configuration. 相似文献
2.
E Miescher 《Journal of Molecular Spectroscopy》1974,53(2):302-310
The spectrum of the electronic NO laser has been photographed with high resolution in the region 10 100–10 500 Å. It shows the band system F2Δ-C2Π whose upper and lower states are both Rydberg states configurationally mixed with valence states. Only predissociated rotational levels of the lower state appear in the spectrum. For v = 0 of C2Π a single mixed level , very close to the dissociation limit, gives rise to laser lines. 相似文献
3.
The high resolution absorption spectrum of CO has been reinvestigated in the Hopfield helium continuum region, particularly from 960 to 1080 Å. The Rydberg state 3pπE1Π was extended to v = 2, and other Rydberg states, and F1Σ+, , and and 1Σ+, which are converging to the X2Σ+ ground state of CO+, have been identified. The rotational structures of only five bands among the observed ten Rydberg bands have been analyzed. 相似文献
4.
The electronic absorption spectra of carbon dioxide and carbon disulfide have been reexamined. Model potential calculations have been used to calculate the energies of excited states in Rydberg approximation, and (npσ) and (npπ) Rydberg series have been assigned. For both molecules, the lowest excited 1Πg and 1Πu states are identified as Rydberg states. The lowest state is mainly Rydberg for CO2, but contains some valence character for CS2, There is no evidence for transitions to additional valence states of these symmetries.It is shown that predictions about excited states can be misleading because of near-linear dependencies which arise in multicenter expansions. A consideration of the united atom orbitals for CO2 and CS2 predicts that there should be only the number of low-energy excited states which are found from the spectral analysis. 相似文献
5.
L Veseth 《Journal of Molecular Spectroscopy》1979,77(2):195-201
The theory of the Zeeman effect in 2Π states of diatomic molecules is reconsidered. Second order terms due to the interaction with 2Δ states, which were left out in a previous investigation, are now included. The total correlation between the spin-rotation coupling constant and the centrifugal distortion in the spin-orbit coupling renders the fitted molecular g factors somewhat ambiguous. This problem is handled by a transformation of the basis for the Hamiltonian matrix. The theoretical results are exemplified for the 2Π ground state of OH for which EPR data are available for both the and substates. A combination of ab initio predictions and fitted values of the g factors finally yields new information concerning the separate contributions from 2Σ+, 2Σ?, and 2Δ states to the contamination of the 2Π ground state in OH. 相似文献
6.
Rotational structure of a series of new absorption bands of PO in the region 1850 to 1600 Å has been analyzed from a spectrum taken at high resolution. The bands are attributed to an electronic transition P2Π-X2Π, where P2Π is a new valence state of PO. Some of these bands have been found to be perturbed. A qualitative account of these perturbations is presented. A probable electron-configuration has been suggested for the new state. From the predissociation observed in the higher vibrational levels of P an upper limit of 48 885 cm?1 (X2Π, T0 = 0) for the ground state dissociation energy has been obtained. 相似文献
7.
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
8.
Thom.H. Dunning William P. White Russell M. Pitzer C.Weldon Mathews 《Journal of Molecular Spectroscopy》1979,75(2):297-317
Multiconfiguration Hartree-Fock calculations are reported on the low-lying valence states, the X2Π, 4Σ?, B2Δ, and 2Σ± states, of carbon monofluoride. The wavefunctions describe dissociation of the molecule to the correct atomic limits and take account of the atomic 2s-2p near-degeneracy effect. For the ground state the calculations give (with experimental values in parentheses): a bond length of 1.286 Å (1.2667 Å), a fundamental frequency of 1292 cm?1 (1308 cm1), and a dissociation energy of 3.93 eV (5.5 ± 0.1 eV). A 4Σ? state arising from the manifold is calculated to lie just 2.66 eV above the ground state. The B2Δ state, calculated adiabatic excitation energy 6.59 eV (6.12 eV), is found to dissociate to via a potential maximum. Calculations are also reported on a repulsive 2Δ state arising from ground state atoms. 相似文献
9.
Robert W. Field Richard A. Gottscho E. Miescher 《Journal of Molecular Spectroscopy》1975,58(3):394-413
No perturbation between two valence states of NO has ever been identified, although many valence-Rydberg and several Rydberg-Rydberg perturbations have been extensively studied. The first valence-valence crossing to be experimentally documented for NO is reported here and occurs between the 15N18O B2Π (v = 18) and B′2Δ (v = 1) levels. No level shifts larger than the detection limit of 0.1 cm?1 are observed at the crossings near and ; two crossings involving higher rotational levels could not be examined. Semi-empirical calculations of spin-orbit and Coriolis perturbation matrix elements indicate that although the electronic part of the interaction is large, a small vibrational factor renders the 15N18O B (v = 18) ? B′ (v = 1) perturbation unobservable. Semi-empirical estimates are given for all perturbation matrix elements of the operators and which connect states belonging to the configurations , , and . 相似文献
10.
Some anomalies in the electronic spectra of GeH,GeD, SnH,and SnD related to Hund's coupling case (c)
L. Veseth 《Journal of Molecular Spectroscopy》1973,48(2):283-291
Expressions for the rotational energy and fine structure based on Hund's coupling case (c) are applied to the 2Π, 4Σ?, and 2Δ states of the heavy hydrides and deuterides GeH, GeD, SnH, and SnD. The 2Π ground state is found to be very well described by the case (a) coupling model, while a considerable case (c) character is found for the 4Σ? state, thus accounting for the observation of the forbidden transition. For the 2Δ state the case (c) model yields very reasonable explanations for several apparent anomalies, in particular for the irregular isotopic shifts of the coupling constants. 相似文献
11.
J.D. Petke Gerald M. Maggiora Lester L. Shipman Ralph E. Christoffersen 《Journal of Molecular Spectroscopy》1978,73(2):311-331
Ab initio configuration interaction wavefunctions and energies are reported for the ground state and many low-lying singlet and triplet states of magnesium chlorin and chlorin, and are employed in an analysis of the electronic absorption spectra of these systems.In chlorin, the calculated visible spectrum consists of two states, the lower energy, y-polarized state exhibiting moderate absorption intensity in contrast to the very weak absorption of the higher energy x-polarized state. The configurational composition of both states is well described by the four-orbital model. Five states are responsible for the Soret band envelope. A moderately intense y-state lies under the low energy edge of the band envelope, while two x-polarized states of moderate and strong intensity, respectively, are responsible for the band maximum. The final two states lie at the high energy edge of the Soret band and introduce a measure of asymmetry into the band envelope. Two states of very weak oscillator strength are also found in this region of the spectrum. All the Soret states are of complex configurational composition, and several of the higher lying states contain contributions from doubly excited configurations.The calculated visible spectrum of magnesium chlorin also consists of two states, with the weakly absorbing x-polarized state lying approximately 200 cm?1 lower in energy than the moderately intense y-polarized state. The configurational composition of both states is well described by the four-orbital model. Four states constitute the bulk of the intensity in the Soret band envelope. In distinction to chlorin, the moderately intense state at the low energy edge of the band envelope is x-polarized. Two intense states of y- and x-polarization, respectively, constitute the band maximum region, and a single x-polarized state of moderately strong intensity can be assigned to the high energy shoulder of the band envelope. Two other weakly absorbing states are also found in this region, along with another weakly absorbing state of mixed in-plane and out-of-plane polarization. No clearly defined states are observed. As was the case for chlorin, all the Soret states are of complex configurational composition, and some of the higher energy states contain significant contributions from doubly excited configurations.Chlorin and magnesium chlorin both possess three states which lie below S1 and a single which lies slightly above S2. All four of the low-lying states in each molecule are well described by the four-orbital model, with T1 being essentially a single configuration in each case. The remainder of the states are clustered in the same energetic region as the comparable Soret states, with comparably complex configurational compositions.Dipole moments and charge distributions for low-lying singlet and triplet states are also reported, and are used to rationalize chemical reactivity characteristics. 相似文献
12.
R. Barloutaud A. Borg F. Brun D. Denegri C. Louedec F. Pierre M. Spiro B. Drevillon B. Chaurand G. Labrosse R. Lestienne D. Linglin R.A. Salmeron T.P. Shah K. Paler R.J. Miller J.J. Phelan 《Nuclear Physics B》1973,59(2):374-411
We have studied the system in the 14.3 GeV/c reactions K?p → K?π+π?p, . The data have been obtained from a 500 000 picture exposure of the CERN 2m HBC. The first two final states are dominated by Q-production in the Kππ system; there is also an L-signal at M (Kππ) ~ 1.75 GeV. The reaction cross sections are compared to K?p data at other energies. We discuss the Kππ mass dependence of the diffractive production slope. Evidence is presented for a Q?p versus Q+p differential cross section cross-over around |t| = 0.17 GeV2. A t-channel isospin analysis for the channels in the Q-region shows that the I = 1 exchange amplitude is of the dominant I = 0 exchange amplitude. The Kππ decay distributions indicate a predominant JP = 1+ state in the Q-region, and an important JP = 2? contribution in the L-region. We find neither s-channel nor t-channel helicity conservation at the meson vertex in the Q- or L-regions. The Kπ angular correlation moments within the Kππ diffractive system are characteristic of Kπ elastic scattering, suggesting a π-exchange Deck-type production mechanism. There is evidence for a Kf0 and κπ contribution (where κ is the JP(Kπ) = 0+ state) to the diffractive Kππ system. A fit to the Dalitz-plot distributions for the Q-re gion indicates that the ratio of decay amplitudes decreases with increasing Kππ mass. 相似文献
13.
We present previously unpublished data on the A1Π, e3Σ?, d3Δi, , and a3Π states of CS from uv emission and absorption transitions to the X1Σ+ ground state. Term values obtained from d3Δi ← a3Π ir emission bands are also included. Rotational analyses are presented for about 50 new fine-structure components in some 30 new vibrational levels, together with extended data and analyses for many of the previously observed levels. The data now availabe for these five electronic states more than triples that previously published. Vibrational numbering for the e, d, and a′ states is established by data for minor isotopes. In a Hund's case a-b basis, off-diagonal spin-orbit elements (incipient case c effects) produce extensive coupling among these levels, not only for perturbation crossings but also between levels widely separated in energy. A systematic deperturbation requires two stages, which are iterated. Term values computed from the spectral lines are used to fit parameters of Hamiltonian matrices for groups of nearby, coupled levels. Additional shifts are computed by second-order perturbation theory from the electronic interactions deduced from vibronic coupling elements. The resultant parameters satisfy certain tests for self-consistency; they conform to low-order polynomials in , and vibrational overlap factors from wave-functions computed with RKR potential curves are proportional to the vibronic coupling elements, to within experimental error in most cases. To obtain this self-consistency, we have computed and applied normally neglected centrifugal distortion effects in the off-diagonal coupling elements and in the second-order perturbation sums. We also present and interpret the diagonal spin-orbit fine structure in the a and d states, including the centrifugal distortion parameters, AD, for the latter, and values for several fitted second-order elements. Possible assignments for three additional perturbations of the A1Π state and one faint band are discussed in view of 1Δ, 1Σ?, and 5Π states that are also expected to occur in the region studied. Tentative parameters for the D1Δ state are obtained from one possible set of assignments. 相似文献
14.
P.M. Heinen J.J. Engelen E.W. Kittel W.J. Metzger M.M. Schouten J.S.M. Vergeest R.T. Van De Walle B. Jongejans H. Voorthuis M. Cerrada R.J. Hemingway S.O. Holmgren M.J. Losty 《Nuclear Physics B》1977,122(3):443-463
A partial-wave analysis of the low-mass (π+π?p) system produced in the reaction K?p → K?(π+π?p) at 4.2 GeV/c incident momentum is performed in order to study the two (π+π?p) enhancements around 1500 and 1700 MeV. It is found that the low-mass (π+π?p) system can be described using the spin-parity states and only. In the 1500 MeV region contributions are observed from the wave decaying into p? and the wave decaying into Δ++π?; in the 1700 MeV region contributions are found from the wave decaying into Δ++π?, the wave decaying into p?, and the wave decaying into p?. 相似文献
15.
G. Mairle G.J. Wagner P. Grabmayr K.T. Knöpfle H. Riedesel K. Schindler V. Bechtold L. Friedrich P. Ziegler 《Nuclear Physics A》1982,382(2):173-184
The reactions have been investigated at Ed = 52 MeV. Vector analyzing powers as large as are observed. They exhibit patterns characteristic for final spins I = |L?1|, L or L + 1 and provide spin determinations at least for states of unique L-transfer. Local, zero-range DWBA calculations assuming deuteron-cluster pick-up reproduce qualitatively the observed effects. The method has been tested for states of known spin, and then has been applied to determine spins of states with stretched coupling in 16N: Jπ = 3+(3.96 MeV), 4?(6.17 MeV) and in 32P: Jπ = 5+(4.75 MeV). There is strong evidence for further 5+ states in 32P at 6.43, 7.96, 8.09 and 8.54 MeV. 相似文献
16.
Shingkuo Shih Sigrid D Peyerimhoff Robert J Buenker 《Journal of Molecular Spectroscopy》1977,64(2):167-179
The vertical transition energies and oscillator strengths from the ground and excited states of the ethynyl radical C2H to all higher-lying states resulting from excitation out of π and σ into and valence-shell MO's, respectively, as well as into 3s and 3p Rydberg species, are calculated by large-scale CI techniques. It is found that the first excited states all result from excitations (the lowest three with quartet character), and not from the 4σ → 5σ counterparts favored in the case of isoelectronic CN. This distinction can be explained on the basis of orbital stability differences caused by the effects of hydrogen mixing. The first six states of the C2H+ ion are also treated, and the correspondence with the various associated Rydberg series is discussed. Dipole moments for the and states are also calculated. 相似文献
17.
D. Sotiriou 《Nuclear Physics B》1976,107(3):457-475
A spin-parity analysis of the nπ+ system produced in the reaction π+p → π+π+n at 16 MeV/c has shown apart from the mass enhancements associated with the known resonances Δ+(1238), N1(1520) and N1(1688) there is an enhancement peaked at M(nπ+) ? 1.35 GeV, ∑0.2 GeV wide. For masses below M(nπ+) ? 1.35 GeV this enhancement is predominantly due to states, predominate. The presence of states indicates that the rule ΔP = (?1)ΔJ is strongly violated in the diffractive process N → Nπ, and hence it cannot be considered a specific characteristic of all diffractive processes. 相似文献
18.
H.H. Bingham C.W. Farwell W.B. Fretter G.M. Irwin S. Kahn A. Lu B. Daugeras D. Fournier J. Hennessy M. Novak J.J. Veillet A.M. Cnops F.R. Huson R.I. Louttit D.J. Miller J.S. ONeall M. Di Carato M. Rollier J. Ginestet 《Nuclear Physics B》1973,52(1):31-69
Coherent production of final states from A ~ 20 nuclei by K? beams of 5.5, 10.0 and 12.7 GeV is analyzed. Final states with ? 2πO are included. Coherent production occurs (although forbidden via 0+ exchange) and is dominated by the 1 (890). The shape of the t distribution, the alignment of the produced meson and the ratio of the cross section on nuclei to that on hydrogen are consistent with optical model predictions assuming that 1 (890) are produced on single nucleons by exchange of isoscalar trajectories of natural parity (JP = 1?, 2+, etc.) and that the 1 (890) absorption in nuclear matter equals that of the K?. Coherent production (allowed via 0+, 1?, 2+, etc. exchange) is dominated by the Q phenomenon. A Dalitz plot and angular correlation analysis yields values for fractions, and shows that dominates the coherently produced Q. The helicity of the Q is found to be compatible with 0. The Q? -nucleaon total cross section is estimated to be 0.98?0.37+024 times the ? -nucleon total cross section from a comparison of the coherent Q-production cross section with corresponding hydrogen cross sections at 10 and 12.7 GeV. We observe coherent production of ω. The ration coherently produced in the Q mass region is (4 ± 1)%. Coherent production of is observed in the L region. Coherent production is not observed in the K4π channels. 相似文献
19.
P. Gregory D. Everett P. Grossmann P. Mason H. Muirhead G. Warren R. Carlsson G. Ekspong S.O. Holmgren S. Nilsson R. Stenbacka C. Walck 《Nuclear Physics B》1974,78(2):222-232
Relations have been derived between the invariant cross sections for various inclusive processes by assuming factorisation of the leading (pomeron) and non-leading (meson) trajectories. In this paper predictions for the invariant cross sections have been tested using data from interactions at 4.6 and 9.1 GeV/c.A large discrepancy between experiment and theory is apparent for the π? data: in the π+ case the discrepancy is less marked but still present. 相似文献
20.
T. Fujii T. Kondo F. Takasaki S. Yamada S. Homma K. Huke S. Kato H. Okuno I. Endo H. Fujii 《Nuclear Physics B》1977,120(3):395-422
The differential cross sections for γp→π+n from hydrogen and the ratios from deuterium were measured at nine c.m. angles between 30° and 150° for laboratory photon energies between 260 and 800 MeV. A magnetic spectrometer with three layers of scintillation hodoscope was used to detect charged π mesons. The cross section for γn→π?p was obtained as a product of and the ratio. The overall features in the cross sections of the two reactions, γp→π+n and γn→π?p, and in the ratios, , agree with predictions by Moorhouse, Oberlack and Rosenfeld, and Metcalf and Walker. An investigation of the possible existence of an isotensor current was made and a negative result was found. In detailed balance comparison with the new results on the inverse reaction π?p→γn, no apparent violation of time-reversal invariance was observed. 相似文献