(γ, 2γ) studies on multiply excited states of H2 and N2 in the vacuum ultraviolet range

Author(s):  
Takeshi Odagiri
Atoms ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 62
Author(s):  
Kin-Fung Lai ◽  
Wim Ubachs ◽  
Nelson De Oliveira ◽  
Edcel J. Salumbides

Accurate Fourier-transform spectroscopic absorption measurements of vacuum ultraviolet transitions in atomic nitrogen and carbon were performed at the Soleil synchrotron. For 14N, transitions from the 2s22p34S3/2 ground state and from the 2s22p32P and 2D metastable states were determined in the 95–124 nm range at an accuracy of 0.025cm−1. The combination of these results with data from previous precision laser experiments in the vacuum ultraviolet range reveals an overall and consistent offset of −0.04 cm−1 from values reported in the NIST database. The splittings of the 2s22p34S3/2 – 2s2p44PJ transitions are well-resolved for 14N and 15N and the isotope shifts determined. While excitation of a 2p valence electron yields very small isotope shifts, excitation of a 2s core electron results in large isotope shifts, in agreement with theoretical predictions. For carbon, six transitions from the ground 2s22p23PJ and 2s22p3s3PJ excited states at 165 nm are measured for both 12C and 13C isotopes.


2003 ◽  
Vol 36 (16) ◽  
pp. 3541-3554 ◽  
Author(s):  
Masahiro Kato ◽  
Takeshi Odagiri ◽  
Kosei Kameta ◽  
Noriyuki Kouchi ◽  
Yoshihiko Hatano

1980 ◽  
Vol 19 (4) ◽  
pp. 765-766 ◽  
Author(s):  
Isamu Kitani ◽  
Katsumi Yoshino ◽  
Yoshio Inuishi

2020 ◽  
Vol 153 (5) ◽  
pp. 054301
Author(s):  
Michael H. Palmer ◽  
Søren Vrønning Hoffmann ◽  
Nykola C. Jones ◽  
Marcello Coreno ◽  
Monica de Simone ◽  
...  

1968 ◽  
Vol 46 (8) ◽  
pp. 987-1003 ◽  
Author(s):  
Ch. Jungen ◽  
E. Miescher

Heterogeneous perturbations 2E+ ~ 2Π of largely different magnitudes are observed with high resolution in the vacuum-ultraviolet absorption and in the infrared emission spectrum of the NO molecule. The rotational interactions between 2Σ+ Rydberg states and levels of the B2Π non-Rydberg state are shown to be "configurationally forbidden", but produced by the configuration interaction between the non-Rydberg levels and 2Π Rydberg states. The latter together with the 2Σ+ Rydberg states form p complexes. In this way the interactions display the l uncoupling in the complexes; they can be evaluated theoretically and can be analyzed fully. The cases of the strong interactions D2Σ+(v = 3) ~ B2Π(v = 16)and D2Σ+(v = 5) ~ B2Π(v = 21) and of the weaker D2Σ+(v = 1) ~ B2Π(v = 11), all three observed as perturbations in ε bands crossing 3 bands, are discussed in detail. It is further shown that perturbations between γ bands and β bands as well as perturbations between analogous bands of higher principal quantum number are absent, and thus the assignment of the A2Σ+ and E2Σ+ states to the s Rydberg series is confirmed.


2015 ◽  
Vol 22 (2) ◽  
pp. 328-335 ◽  
Author(s):  
Chaofan Xue ◽  
Yanqing Wu ◽  
Ying Zou ◽  
Lian Xue ◽  
Yong Wang ◽  
...  

A new monochromator called an extra-focus constant-included-angle varied-line-spacing (VLS) cylindrical-grating monochromator (extra-focus CIA-VCGM) is described. This monochromator is based on the Hettrick–Underwood scheme where the plane VLS grating is replaced by a cylindrical one in order to zero the defocus at three reference photon energies in the vacuum-ultraviolet range. It has a simple mechanical structure and a fixed focus spot with high performance over a wide energy range. Furthermore, its mechanical compatibility with a standard VLS plane-grating monochromator allows convenient extension into the soft-X-ray range.


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.


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