Extensions to the spectrum of doubly excited Mg I in the vacuum ultraviolet

The absorption spectrum of Mg I vapour between 2000 and 700 ņ has been reinvestigated, using the continuum emitted by the Bonn 500 MeV electron synchrotron as the source of background radiation. Extensions to the double excitation spectrum of the valence shell have resulted and are compared with recent data obtained by electron impact spectroscopy. Ab initio calculations of the doubly excited configurations have been extended to high series members, and the transition from LS to jj coupling is shown to be responsible for the appearance of a 1 S 0 - 3 P 1 series not previously detected by photoabsorption.

The absorption spectrum of Ag I between 550 Å and 1590 Å has been investigated by using synchrotron radiation as the source of continuum. Over 50 new transitions are reported, nearly all of which can be classified into Rydberg series due to excitation of one electron from the 4d subshell. Identifications are made by comparison with previous studies of the arc spectrum as well as with absorption spectra of related elements. Ab initio Hartree-Fock calculations have revealed the importance of treating 5s 5p 1 P based levels by a separate variational method. Doubly excited configurations are also found, but, in contrast to a previous theoretical prediction, double vacancy production within the 4d subshell is not found to be significant for Ag I.


1976 ◽  
Vol 54 (5) ◽  
pp. 525-567 ◽  
Author(s):  
I. Dabrowski ◽  
G. Herzberg

The absorption spectrum of HD has been studied under high resolution in the vacuum ultraviolet to 840 Å, the emission spectrum to 1000 Å. The analysis of the latter gives accurate rotational constants and vibrational intervals of the ground state right up to the dissociation limit. Comparing these experimental data with calculations from ab initio theory, agreement to the same extent as was previously found for H2 and D2 is obtained. Extrapolation of the obs. – calc. values from H2 and D2 to infinite mass yields agreement with the recently revised theoretical values to within less than 0.1 for v < 7 and less than 0.5 cm−1 for the whole range of observed v values. The deviations for finite mass (H2 and D2) are clearly due to the non-adiabatic corrections neglected in the ab initio calculations. The results for HD are not halfway between H2 and D2 but are closer to H2. This apparent anomaly can be quantitatively accounted for, on the basis of recent calculations of Wolniewicz, by the effect of additional nonadiabatic corrections caused by the excited Σu states which in HD, unlike H2 and D2, can interact with the ground state.The rotational and vibrational constants of the excited states B1Σu+, C1Πu, and B′1Σu+ show somewhat larger deviations from ab initio values ranging for v0v from 5 to 120 cm−1, just as for H2 and D2. The electronic isotope shift of HD lies approximately half-way between the values of H2 and D2 as expected. In addition to the B–X, C–X, and B′–X systems the absorption spectrum of HD, unlike that of H2 and D2, shows an extensive progression of weak transitions to the double minimum state EF1Σg+ and a few very weak transitions to the G1Σg+ and I1Πg states. For the EF state both levels in the outer minimum (F) and levels above the maximum are observed. The correlation of the six excited states B, C, B′, EF, G, and I to the two close-lying dissociation limits corresponding to H + D* and H* + D is briefly discussed.


The Sr I absorption spectrum between 300 and 800Å|| has been photographed, and nearly 200 new lines have been revealed. Two methods are used to analyse the spectrum. First, comparison with multiconfiguration Hartree-Fock calculations is used to identify first series members and, secondly, simplified Lu-Fano plots are used to order other lines into Rydberg series. Identifications are also provided for many lines of the Sr 4p-subshell ejected-electron spectrum, excited by electron impact (White et al. 1979). In particular eighteen SrII levels are identified.


1978 ◽  
Vol 56 (7) ◽  
pp. 962-973 ◽  
Author(s):  
Yumio Morioka ◽  
Harunobu Masuko ◽  
Masatoshi Nakamura ◽  
Michio Sasanuma ◽  
Eiji Ishiguro

The absorption coefficients of NO2 in the region from 500 to 1100 Å are measured by a photographic method using the radiation from electron synchrotron as a background source. For the Rydberg series due to the transition from 4a1 to npπ, parameters q and Γ in Mies equation are obtained and the parameter q is determined to be −0.4 for every member and Γ 4.808/n*3 eV where n* is the effective quantum number.The absorption spectrum of NO2 in the region from 600 to 1600 Å are also analyzed. New vibrational progressions that are observed around 950 Å, are assigned to the excitations from 4b2 to ns Rydberg states (n = 3, 4, and 5) converging to the 1B2 ionic state. Assignments and discussions of many other Rydberg series that appear in the absorption spectrum between 600 and 1600 Å are also presented.


1979 ◽  
Vol 57 (5) ◽  
pp. 745-760 ◽  
Author(s):  
Harunobu Masuko ◽  
Yumio Morioka ◽  
Masatoshi Nakamura ◽  
Eiji Ishiguro ◽  
Michio Sasanuma

The optical absorption spectrum of the H2S molecule in the region from 2050 to 1150 Å has been studied by a photographic method, using the radiation from a 1.3-GeV electron synchrotron as a background source. Numerous bands including those due to dipole forbidden transitions are observed in the spectrum. Five types of Rydberg series are assigned to electronic transitions from the outermost 2b1 orbital to the d-like orbitals, three types to the p-like orbitals, and one type to the s-like orbital. The quantum defects of these transitions and a series limit of 84 417 ± 8 cm−1 (10.466 ± 0.001 eV) were determined using the extended Rydberg series. The first member of the A Rydberg series splits into four bands, which is discussed with jj coupling scheme. The upper state of the 2000-Å (6.20-eV) broad band is assigned to the (2b1)−1 (6a1/4sa1) 1B1 state which is predominantly of valence orbital character. Transitions to vibrationally excited state were also investigated and the limit to which the (100) vibrationally excited Rydberg series converges was determined to be 86 882 ± 20 cm−1 (10.772 ± 0.003 eV). The results obtained in this experiment are compared with theoretical calculations.


2002 ◽  
Vol 09 (01) ◽  
pp. 615-619
Author(s):  
MASANORI KAKU ◽  
TAKAHIRO YAMAURA ◽  
SHOICHI KUBODERA ◽  
WATARU SASAKI

Vacuum ultraviolet (VUV) continua emitted from a laser-produced plasma have been utilized for the spectroscopy of a solid state laser material. An absorption spectrum of 0.1% Nd:LaF 3 has been measured by use of the continuum emission. The minimum absorption coefficient of 1.4 cm -1 was evaluated at 174 nm.


2020 ◽  
Vol 124 (52) ◽  
pp. 10997-11005
Author(s):  
Li-Han Wang ◽  
Xiao-Jiao Du ◽  
Yuan-Chen Xu ◽  
Tian-Jun Li ◽  
Zi-Ru Ma ◽  
...  

Author(s):  
Paul Brint ◽  
Jean-Patrick Connerade ◽  
Pericles Tsekeris ◽  
Agisilaos Bolovinos ◽  
Aslam Baig

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