PHOTO-IONIZATION OF N2 IN THE 734–805 Å REGION

1965 ◽  
Vol 43 (2) ◽  
pp. 256-267 ◽  
Author(s):  
G. R. Cook ◽  
M. Ogawa
Keyword(s):  
Ionization Potential ◽  
High Efficiency ◽  
Ion Current ◽  
Rydberg Series ◽  
Absorption Bands ◽  
Quantum Numbers ◽  
Ionization Coefficients ◽  
Photo Ionization ◽  
Vacuum Monochromator ◽  
First Ionization Potential

Absolute photo-ionization coefficients and ionization efficiencies of N2 have been measured in the 734–805 Å region using a 1-meter Seya–Namioka scanning vacuum monochromator with the Hopfield helium continuum as a background light source.The ion-current spectrum obtained has been compared with the absorption spectrum observed photographically. Nearly all of the absorption bands with higher energies than the first ionization potential showed ion-current peaks, indicating pre-ionization. However, their ionization efficiencies showed strong fluctuations whose magnitudes decreased toward the shorter wavelengths. The spectral regions with the lowest absorption coefficients (180–340 cm−1) beyond the first ionization potential showed the highest efficiencies, the values of which were about 80%. Efficiencies of bands with m[Formula: see text] of the Ogawa–Tanaka Rydberg series were much larger than those of the corresponding bands of the Worley third Rydberg series. The progressions (1) and (2) had a rather high efficiency of 70% which increased slightly with an increase of the vibrational quantum numbers of the upper electronic states.

Rydberg series and autoionization resonances in the Y I absorption spectrum

1973 ◽  
Vol 333 (1592) ◽  
pp. 17-24 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Ionization Potential ◽  
Excited States ◽  
Spectral Range ◽  
Ground State ◽  
Rydberg Series ◽  
A Value ◽  
Doublet Ground State ◽  
Ionization Limit ◽  
First Ionization Potential

The absorption spectrum of yttrium vapour has been photographed in the spectral range 1650 to 2250 À, with a 10 m spectrograph. Series of autoionization resonances, which converge on excited states of the Y + ion have been identified, as combinations with the doublet ground-state of Y I , 5s 2 4d 2 D 3/2 , 5/2 . Although the lines of these series show broadened and often asymmetrical profiles, the lines are sufficiently well defined to fix a value for the first ionization potential of Y I , which differs from the previously accepted value by approximately 2500 cm -1 . In addition, approximately 400 new Y I lines, which involve excited levels below the first ionization limit of Y I , namely 4s 2 1 S o , have been found. The majority of these are unclassifiable at present but, the value for the first ionization-potential being known from the resonances above-mentioned, two series of the character 5s 2 4d 2 D 3/2 , 5/2 -5s 2 nf 2 F o have been identified. In addition to the identifications of series, 152 new lines below the 5s 2 1 S o limit identify 76 new levels of Y I , of odd parity.

scholarly journals The absorption spectra of benzene derivatives in the vacuum ultra-violet. I

1947 ◽  
Vol 191 (1024) ◽  
pp. 22-31 ◽  
Keyword(s):  
Ionization Potential ◽  
Absorption Spectra ◽  
Ultra Violet ◽  
Benzene Derivatives ◽  
Rydberg Series ◽  
First Ionization Potential ◽  
Vacuum Ultra Violet

New photographs of the far ultra-violet spectrum of benzene are presented. The absorption from 2000 to 1800A ( λ max , c . 1980A) is regarded not as a part of the much stronger absorp­tion of peak at 1790A but as due to a separate transition. Sharp bands lying at 1790A represent the first member of a previously reported Rydberg series. The spectra of toluene, xylene, monochloro-and o -dichlorobenzene, bromobenzene, iodoben-zene and pyridine are briefly described, and the shifts relative to benzene are discussed. Two Rydberg series were observed for toluene, converging to a first ionization potential of 8.77 ± 0.05 V.

The photoabsorption of chlorodifluoroethenes in the vacuum ultraviolet

1985 ◽  
Vol 63 (7) ◽  
pp. 1949-1954 ◽  
Author(s):  
Eckart Rühl ◽  
Hans-Werner Jochims ◽  
Helmut Baumgärtel
Keyword(s):  
Energy Range ◽  
Ionization Potential ◽  
Gas Phase ◽  
Absorption Spectra ◽  
Photon Energy ◽  
Vacuum Ultraviolet ◽  
Rydberg Series ◽  
Absorption Bands ◽  
Broad Absorption ◽  
Cis And Trans

The gas phase absorption spectra of 2-chloro-1,1-difluoroethene, cis- and trans-1-chloro-1,2-difluoroethene have been measured in the photon energy range from 6.5 to 25 eV. The π → π* transition is assigned to bands centered around 7.17 – 7.20 eV for all three isomers. Four Rydberg series are observed in all the spectra, converging to the π ionization potential: two np-type Rydberg series, one ns, and one nd series are assigned. The convergence limits are: 9.84 eV (2-chloro-1,1-difluoroethene), 9.86 eV (trans-1-chloro-1,2-difluoroethene), and 9.85 eV (trans-1-chloro-1,2-difluoroethene). In the case of 2-chloro-1,1-difluoroethene four additional Rydberg series are found converging to the nCl ionization potential. The convergence limit of these series is 12.15 eV.Above 12 eV broad absorption bands dominate the spectra.

The far ultra-violet absorption spectra of the hydrides and deuterides of sulphur, selenium and tellurium and of the methyl derivatives of hydrogen sulphide

1950 ◽  
Vol 201 (1067) ◽  
pp. 600-609 ◽  
Keyword(s):  
Ionization Potential ◽  
Absorption Spectra ◽  
Ground State ◽  
Lone Pair ◽  
Ultra Violet ◽  
General Nature ◽  
Rydberg Series ◽  
Group Vi ◽  
Methyl Derivatives ◽  
First Ionization Potential

The absorption spectra in the vacuum ultra-violet of the hydrides and deuterides of sulphur, selenium and tellurium, and methyl mercaptan and dimethyl sulphide are described. Well-developed Rydberg series leading to the following ionization potentials have been found: H 2 S, 10.47V; MeSH, 9.44V; H 2 Se, 9.88V; H 2 Te, 9.14V. In the case of one series for H 2 Se fifteen members of the series were observed. The spectra of the deuterides are almost identical with those of the hydrides, showing that virtually every band in the spectra is due to a separate electronic transition. This and the general nature of the rotational fine structure show the transitions concerned to be those of an electron from a non-bonding ground-state orbital, i.e. from the p lone-pair ground-state orbital. The nature of the upper orbitals of the various series is also interpreted and shown to provide explanations of certain peculiarities of the observations. The quantity I(X) — J(H 2 X), where X is a group VI element, or I ( Y ) — I ( HY), where Y is a group VII element, is shown to be positive and comparatively large when X or Y lies in the first period of the periodic table, but to change sign and to remain almost constant at a small negative value as one passes to elements in later periods. A plot of I (H 2 X)against the first ionization potential of the corresponding inert gas is linear. Extrapolation enables the first ionization potential of H 2 Po to be predicted at 8.6V. A similar plot for the halogen acids, if assumed linear, yields a predicted first ionization potential for HF of 17.0±0.7V.

The absorption spectrum of diacetylene in the vacuum ultraviolet

1967 ◽  
Vol 300 (1463) ◽  
pp. 519-533 ◽  
Keyword(s):  
Ionization Potential ◽  
Vacuum Ultraviolet ◽  
Vibrational Analysis ◽  
Fermi Resonance ◽  
Ultraviolet Region ◽  
Rydberg Series ◽  
A Value ◽  
The Mean ◽  
Positive Ion ◽  
First Ionization Potential

The spectra of diacetylene- h 2 and diacetylene- d 2 have been photographed in the vacuum ultraviolet region as far as 1000 Å. Comparison of the spectra of the normal and deuterated molecules has led to an extensive vibrational analysis. A revised assignment of the Rydberg origin bands is proposed. This gives a new spectroscopic value of the first ionization potential of 10.180 ± 0.003 eV, in agreement with the electron impact value. Some bands at shorter wavelengths are arranged in a new Rydberg series leading to the second ionization potential, for which a value of 12.62 ± 0.04 eV is found. The results of the analysis correlate in a satis­factory way with the 'T' spectrum of the diacetylene positive ion. The mean of the first and second ionization potentials of diacetylene is found to be equal within experimental error to the first ionization potential of acetylene. Some anomalous features of the spectrum are noted and discussed. The Fermi resonance in the ‘T’ spectrum between v 3 and 2 v 7 is also discussed, and it is concluded that the current assignment should be reversed.

The absorption spectrum of diatomic phosphorus between 1370 and 600 Å

1975 ◽  
Vol 342 (1628) ◽  
pp. 93-111 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Ionization Potential ◽  
Dissociation Energy ◽  
Ground State ◽  
Molecular Orbitals ◽  
The Other ◽  
Ultraviolet Absorption Spectrum ◽  
Rydberg Series ◽  
Far Ultraviolet ◽  
First Ionization Potential

Nine Rydberg series have been observed in the far ultraviolet absorption spectrum of P 2 . Four of these converge to the.(5σ g ) 2 (2π u ) 3 , 2II u (inv.) state of the ion which is established as being the ground state; four to the low-lying ...(5σ g ) (2π u ) 4 , A 2 Ʃ g + state and one to a newly identified (5σ g ) (2π u )3 2πg, F 2 Ʃ + u state. The first ionization potential is found to be 85 229 ± 15 cm-1 (10.567 ± 0.002eV), which is the limit corresponding to the upper component (2II1/2 ) of the inverted X 2II u state. The other limits are observed at 87 179 + 2cm -1 (A 2 Ʃ + g ) and 125 225 ± 10cm -1 (F 2 Ʃ + u ). The series have been interpreted in terms of molecular orbitals and are found to involve excitation of n sσ g , n dσ g , n dπ g and n dδ g for the X 2 II u core; n pπ u , n fσ u , and n fπ u for the A 2 Ʃ + g core and for the A 2 Ʃ + u core. The evaluation and identification of the series limits enables the relative positions of the states of P + 2 to be established. The dissociation energy of P + 2 is estimated to be 4.98 ± 0.01eV.

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