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1.
This report presents i) various characteristic features in photoionization cross sections (σPI) of Cl II + hν  →  Cl III + e for many fine structure levels of Cl II, 392 in total with n ≤ 10 and l ≤ 9, ii) comparison of features with those observed in an experiment carried out at the Advanced Light Source at Lawrence Berkeley National Lab, and iii) partial photoionization cross sections of the ground level for ionization leaving the core ion in to various excited levels for applications in plasma modeling. The features correspond to resonant structures, the shape of the background, and their interference effect in σPI of this near neutral ion Cl II with 16 electrons. σPI for the 5 levels of the ground configuration 3s23p4(3P0,1,2, 1D2, 1S0) of Cl II show regions of narrow Rydberg resonances at and near threshold energies, and resonant structures at higher energies in contrast to typical smooth decrease in the background. Various other features in σPI of levels of excited equivalent electron states and broad Seaton resonances in single valence electron excited levels are illustrated with examples. Comparison of calculated σPI of the 15 lowest levels with the combined features of the measured photoionization spectrum shows excellent agreement by reproducing and thus identifying them to the levels that they belong to. The calculations were carried out in relativistic Breit-Pauli R-matrix (BPRM) method using a close coupling wave function expansion of 45 levels up to 4s of the core ion Cl III. These levels were optimized using a set of 12 configurations going up to orbital 5s, 3s23p3, 3s3p4, 3p5, 3s23p23d, 3s23p24s, 3s23p24p, 3s23p24d, 3s23p24f, 3s23p25s, 3s3p33d, 3s23p3d2, 3p43d producing 283 levels of Cl III. The autoionizing resonances are delineated with a fine energy mesh to observe the fine structure effects. The present results will provide high precision parameters for various applications involving this less studied ion.  相似文献   

2.
Photoionization cross sections of (Ca XV + hν → Ca XVI + e), with high energy resonant photo-absorption phenomena, of a large number of bound states, 701 in total with n ≤ 10 and l ≤ 9, are reported. They are obtained using the R-matrix method with a close coupling (CC) wavefunction expansion of 29 states of n = 2,3 complexes of the core ion Ca XVI. Characteristic features found in photoionization of the ion are illustrated with examples. The cross section (σPI) of the ground 2s22p2(3P) state is found to be unaffected by the size of the wavefunction expansion except for weak sparse resonances in high energy region. However, effects on excited states are considerable as the core excitations to n = 3 states are manifested in huge resonant absorption in high energy photoionization. They show existence of prominent high peak resonant features and enhancement in the background that were not studied before for Ca XV. In addition photoionization of the excited states with a single valence electron is dominated by Seaton resonant structures formed by the photo-excitation-of-core in the high energy region. These features will impact other quantities, such as the opacity, electron-ion recombination in high temperature plasmas where the ion exists, and hence will play important role in determination of elemental abundances in the astronomical objects.  相似文献   

3.
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4.
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5.
Detailed photoionization of ground and many excited states with autoionizing resonances of neutral Ti are presented. Ti I with 22 electrons forms a large number of bound states, the present work finds a total of 908 bound states with n ⩽ 10 and l⩽8. Photoionization cross sections (σPI) for all these bound states have been obtained. Calculations were carried out in the close-coupling R-matrix method using a wave function expansion that included 36 states of core ion Ti II. It is found that the resonances enhance the low energy region of photoionization of the ground and low lying excited states. The resonant features will increase the opacity, as expected of astrophysical observation, and hence play important role in determination of abundances in the elements in the astronomical objects. The excited states also show prominent structures of Seaton or photo-excitation-of-core resonances.  相似文献   

6.
Semi-relativistic calculations are performed for the photoionization of Fe X (an important coronal ion) from its ground state 3s23p $^{5}(^{2}P^{0}_{3/2})$ and the first two excited states 3s23p $^{5}(^{2}P^{0}_{1/2})$ and 3s3p $^{6}(^{2}S_{1/2})$ using the Breit?CPauli R-matrix method. A lowest 41 state eigenfunction expansion for Fe XI is employed to ensure an extensive treatment of auto ionizing resonances that affect the effective cross-sections. In the present calculations, we have considered all the important physical effects like channel coupling, exchange and short range correlation. The present calculations using the lowest 41 target levels of Fe XI in the LSJ coupling scheme are reported and we expect that the present results should enable more accurate modelling of the emission spectrum of highly excited plasma from the optical to the far UV region.  相似文献   

7.
Theoretical populations of the 2s3l levels of Ne vii are presented for electron temperatures from 2.5 × 105 K to 4 × 106 K and electron densities from 108 cm–3 to 1012 cm–3. These, in conjunction with intensities of previously observed solar Ne vii lines and wavelengths and intensities observed in the laboratory, are used to identify further Ne vii lines in the solar spectrum. The dependence on temperature of intensity ratios such as I(2s2p 1 P – 2s3d 1 D)/I(2s2p 3 P – 2s3d 3 D) is demonstrated and the advantages of the small wavelength separation of such lines for solar electron temperature diagnostics are discussed.  相似文献   

8.
New experimental techniques have yielded several thermal energy vibrational quenching rate constants for O2+(v). Rates for quenching of O2+(v = 1) by O2, N2, Ar, CO2, H2, and CH4 are 3(?10), 2(?12), 1(?12), 1(?10), 2.5(?12), and 6(?10) cm3s?1 at 300 K. The quenching is somewhat faster for O2+(v = 2). The triatomic ions CO2+, NO2+, N2O+, SO2+, and H2O+ are all vibrationally deexcited with an efficiency greater than 10?3 in Ar or Ne collisions. A theoretical rationalization of the experimental results leads to the prediction that vibrational quenching in planetary atmospheres will generally be efficient, k > 1(?12) cm3s?1 for almost all ion and neutral gas pairs.  相似文献   

9.
M. Blaha 《Solar physics》1971,17(1):99-116
Equilibrium population of Fexiv levels in coronal conditions was calculated including configurations 3s 23p, 3s3p 2, 3s 23d, 3p 3, 3s3p3d, 3s 24s, 3s 24p, 3s 24d, 3s 24f. Relative populations of selected levels are given in Table VII. Figure 1 shows the dependence of relative intensities of the strongest lines on electron density. Certain line ratios can be used for the determination of N e .E.g., at T=2 × 106 K and with a dilution factor 0.4, the intensity ratio of λ211.3 and λ219.0 changes by a factor of 65 if N e increases from 107 to 1011 (Table VIII). Cascades from the 3s3p3d and 3p 3 configurations are important in the population of some levels of 3s3p 2 (Table VI). A possibility of identification of additional lines in the solar spectrum is indicated. NAS-NRC Resident Research Associate.  相似文献   

10.
The energy differences between 1s 22p 1s2p3p transitions and the corresponding 1s 2 1s3p resonances are expressed by means of a polynomial function of the atomic number. The agreement with experimental data from lithium to potassium is very good. Interpolated values for nitrogen to sodium and argon as well as extrapolation for calcium are reported.  相似文献   

11.
The recent level population calculations for Ne v by Aggarwal are used to determine the theoretical emission line ratios R 1 = I(2s2p 3 1Do - 2s22p2 1De)/I(2s2p3 3D 2 0 - 2s22p2 3P 1 e ) and R 2 = I(2s2p 3 1Do-2s22p2 1De)/I(2s2p 3 3D 3 0 -2s22p2 3P 2 e ). A comparison of these with observational data for a solar flare and erupting prominence obtained with the NRL XUV spectrograph on board Skylab reveals that R 1 and R 2 are in their predicted high density limits. Although the ratios cannot be used as density diagnostics for values of n e typical of the solar transition region, it is shown that they are temperature sensitive and hence may be employed to determine the electron temperatures of Ne v line emitting regions.  相似文献   

12.
Svensson  L. Å.  Ekberg  J. O.  Edlén  B. 《Solar physics》1974,34(1):173-179
The levels of the configuration 3s 23 p 53d of Fe ix have been experimentally determined from their combinations with 3s3 p 63d 3 D in the region 300–400 Å. Wavelengths can now be accurately predicted for all transitions within 3s 23 p 53d, and eight of these can be identified with coronal lines from 2042 to 4585 Å. Also, identifications of solar lines from 171 to 245 Å with electric-dipole and magnetic-quadrupole transitions to the ground state, 3s 23p 6 1 S, are confirmed and extended. Solar identifications with corresponding transitions in Ni xi, both within 3s 23 p 53d and to the ground state, are proposed on the basis of a short extrapolation.  相似文献   

13.
The galactic dynamical system expressed by a third-order axisymmetric polynomial potential is investigated numerically by computing periodic solutions. We define as Sthe compact set of initial conditions generating bounded motions, and as S p , with S p ? S, the countable set of all initial conditions generating periodic solutions. Then, we consider the subsets S s p and S a p of S p , where S s p ∪ S a p = S p , S s p S a p = Ø, the first of which corresponds to symmetric periodic solutions, and the second to asymmetric solutions. Then, we approximate the set S s p , leaving treatment of the set S a p of asymmetric solutions for a future publication. The set S s p is known to be dense in S (‘Last Geometric Theorem of Poincar;’, Birkhoff, 1913). Using a computer programme capable to locate all elements of the set S s p that generate symmetric periodic solutions that re-enter after intersecting the axis of symmetry from 1 to ntimes. The results of the approximation of S s p in the total domain and in the sample sub-domains of zooming, we present in graphical form as family curves in the (x, C) plane. The solutions located with the largest periods re-enter after 440 galaxy revolutions while the families calculated fully (initial conditions, period, energy, stability co-efficient) include solutions that re-enter after 340 galaxy revolutions. To advance further the approximation of the set S s p thus obtained, we applied the same procedure inside eight sub-domains of the domain Sinto which we ‘zoomed’ through selection of finer search steps and double maximum periods. The family curves thus calculated presented in the (x, C) plane do not intersect anywhere in some sub-domains and their pattern resembles that of laminar flow. In other sub-domains, however, we found family curves from which branching families emanate. The concepts of completeand non-completeapproximation of S s p in sub-domains of laminar and sub-domains with branching family curves, respectively, is introduced. Also, the concept of basic family of order1, 2, ..., n, are defined. The morphology of individual periodic solutions of all families is investigated, and the types of envelopes found are described. The approximate set S s p was also checked by computing Poincar; sections for energy values corresponding to the mean energy range of the eight sub-domains of zooming mentioned above. These sections show that most parts of the compact domain in Sgenerating non-periodic but bounded solutions correspond to with well-shaped tori that intersect the x-axis, a fact that implies that dominant to exclusive type of periodic solutions are the symmetric ones with two normal crossings of this axis. The presence of non-symmetric periodic solutions as well as of chaotic regions is encountered. All calculations reported here were performed using the variable step R-K 8th-order direct integration and setting the allowable energy variation Δ C= |C start? C end| < 10?13. The output, consisting of many thousands of families and their properties (initial conditions, morphology, stability, etc.), is stored in a directory entitled ‘Atlas of the Symmetric Periodic Solution of the Galactic Motion Problem’.  相似文献   

14.
The experimentally known energies of the 1s 22s 1s2s(1 S, 3 S)3p transitions are considered for lithium to calcium. Their differences from the corresponding He-like resonances are fitted to the atomic number by means of a polynomial function and, through interpolation, the wavelengths for nitrogen to sodium are calculated.  相似文献   

15.
R. Glass 《Solar physics》1982,78(1):29-38
We have used configuration interaction wavefunctions to calculate energy levels, wavelengths, oscillator strengths and transition probabilities for spin-orbit electric dipole transitions between the 2s 2, 2s2p, and 2p 2 states in beryllium-like ions (Z = 6–10). Some significant differences with previous calculations are obtained. A common set of radial functions is used.  相似文献   

16.
Recent calculations of electron impact excitation rates in He-like Alxii are used to derive the theoretical electron temperature and density sensitive emission line ratios G ( = (f + i)/r and R ( = f/i, where f, i, and r are the forbidden 1s 2 1 S ? 1s2s 3 S, intercombination 1s 2 1 S ? 1s2p 3 P and resonance 1s 2 1 S ? 1s2p 1 P transitions, respectively. These ratios are found to be significantly different from earlier calculations, and are in much better agreement with X-ray spectral data for two solar flares obtained with the SMM and P78-1 satellites.  相似文献   

17.
Expected wavelengths and relative intensities are obtained, from calculations of other workers, for the hitherto unobserved transitions 2p 53p(1 S 0)-2p 53s(1 P 1, 3 P 1) in Fe xvii. A candidate pair of lines at 197.05 Å and 242.09 Å was found in laboratory spectra and appears to be present in the spectra of a solar active region observed by the OSO-7 Goddard spectroheliograph, and in the spectrum of a Skylab-observed solar flare.  相似文献   

18.
A study of theZ-dependence of the2 P intervals of 2s 22p and 2s 22p 5, aided by recent observational results, confirms the identification in the coronal spectrum of λ 4412 with Arxiv, and of λ 5533.4 with Arx. It is further shown that transitions from metastable levels in the configurations 3s 23p k 3d, withk=3, 4 and 5, of Fexi,x, ix, and Nixiii, xiii, xi can well account for the remaining unidentified coronal lines.  相似文献   

19.
Electric quadrupole transition probabilities for transitions between the 2s 2, 2s2p, and 2p 2 states in the beryllium isoelectronic sequence are evaluated using configuration interaction wavefunctions for 6≤Z≤26. It is found that the contribution from the electric quadrupole transitions is negligible and will not be an important process in any laboratory or astrophysical process.  相似文献   

20.
Energy levels and oscillator strengths among the 27 fine-structure levels belonging to the (ls22s2)2p6, 2p53s, 2p53p and 2p53d configurations of the neon-like iron ion have been calculated using three atomic structure codes RCN/RCG, AUTOSTRUCTURE (AS) and GRASP. Relativistic corrections of the wave functions are taken into account in the RCN/RCG calculation. The results agree well with the available experimental and theoretical data. The accuracy of the three codes is analysed.  相似文献   

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