The 1650-1350 Å absorption spectrum of nitrogen dioxide

1962 ◽  
Vol 267 (1330) ◽  
pp. 395-407 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Nitrogen Dioxide ◽  
Ionization Potential ◽  
Ground State ◽  
Band System ◽  
Anharmonic Constant ◽  
Rydberg Transitions ◽  
First Ionization Potential

An analysis of the 1650-1350 Å band system of nitrogen dioxide has been carried out. A pattern of band spacings and intensities is found that is complex but regular. It is shown that this pattern is qualitatively, and to a large extent quantitatively, just what would be expected for a transition in which the shape of the molecule changes from bent to linear. The transition is a parallel one and the upper state has 2 Σ + u symmetry. The symmetrical stretching frequency is increased from its ground-state value to ca. 1420 cm -1 in the upper state. The upper-state bending frequency is ca. 600 cm -1 . The N — O length is decreased from its groundstate value, probably to 1·1(3) Å. The upper state resembles closely the ground state of NO + 2 . The transition is to be classed as one of the Rydberg transitions leading to the first ionization potential of NO 2 ; and the orbital to which the odd electron is transferred in the transition is (pσ) in type. The anharmonic constant g 22 for the linear upper state is found to be 2·(3) cm -1 . Other Rydberg transitions may well be present in the region, but have not been definitely identified.

The vacuum ultraviolet spectrum of the bromine molecule

1969 ◽  
Vol 47 (22) ◽  
pp. 2525-2538 ◽  
Author(s):  
Putcha Venkateswarlu
Keyword(s):  
Absorption Spectrum ◽  
Ionization Potential ◽  
Ground State ◽  
Vacuum Ultraviolet ◽  
Band System ◽  
Rydberg States ◽  
Ultraviolet Spectrum ◽  
Similar Series ◽  
Ionization Limit ◽  
Rydberg Transitions

The absorption spectrum of bromine has been photographed in the first and higher orders of a 10.7-m. concave vacuum grating spectrograph in the region 1700–1170 Å.A number of band systems have been obtained in the region 1510–1170 Å, most of which correspond to Rydberg transitions. In addition, an extensive band system with closely-spaced bands degraded to longer wavelengths has been recorded in the region 1700–1500 Å. Among the Rydberg systems, five series have been found to converge to 85 165 ± 80 cm−1 which represents the ionization potential of the molecule leading to the 2Π3/2g state of the molecular ion. They arise due to transitions from the ground state to [σg2πu4πg32Π3/2g]npσu, [σg2πu4πg32Π3/2g]npπu, [σg2πu4πg32Π3/2g]nfσu, [σg2πu4πg32Π3/2g]nfπu, and [σg2πu4πg32Π3/2g]nfδu configurations where n takes the running values 5, 6, 7, … etc. The first few members of four similar series corresponding to the transitions to the states involving the [σg2πu4πg32Π1/2g] core have been identified and the ionization limit of these series is estimated to be at 88 306 ± 80 cm−1. Two of the remaining band systems have been found to be very likely due to transitions to the Rydberg states with the configurations [σg2πu3πg42Π3/2u]5sσg and [σg2πu3πg42Π1/2u]5sσg, respectively. Three of the observed systems which do not involve Rydberg states appear to have for their upper levels the 1Πu(1u), 3Π(1u), and 3Π(0u+) states arising from the configuration σgπu3πg4σu2.

The Vacuum Ultraviolet Spectrum of ICI

1975 ◽  
Vol 53 (8) ◽  
pp. 812-824 ◽  
Author(s):  
Putcha Venkateswarlu
Keyword(s):  
Absorption Spectrum ◽  
Ionization Potential ◽  
Ground State ◽  
Vacuum Ultraviolet ◽  
Band System ◽  
Ultraviolet Spectrum ◽  
Similar Series ◽  
Iodine Chloride ◽  
Rydberg Transitions ◽  
Concave Grating

The absorption spectrum of iodine chloride has been photographed in the high orders of a 10.7 m concave grating spectrograph in the region 1900–1220 Å. A number of band systems which correspond to Rydberg transitions have been obtained. In addition an extensive band system with closely spaced bands degraded to longer wavelengths has been observed in the region 1660–1580 Å. Among the Rydberg systems, 12 series have been found to converge to 81 362 ± 80 cm−1 which very likely represents the ionization potential of the molecule leading to the 2Π3/2 state of the molecular ion. They are due to transitions from the ground state to states arising from the configurations (σ2π4π32Π3/2)ns σ, (2Π3/2)np σ, (2Π3/2)np π, (2Π3/2)nd σ, (2Π3/2)nd π, (2Π3/2)nd δ, (2Π3/2)nf σ, (2Π3/2)nf π, and (2Π3/2)nf δ where n takes the running values 6, 7, 8, … for the first three configurations, 5, 6, 7, … for the next three configurations, and 4, 5, 6, … for the last three configurations. The first few numbers of 11 similar series corresponding to the transitions to the states involving the (σ2π4π32Π1/2) core have been identified and the ionization of these series is estimated to be at 85 996 ± 80 cm−1.

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.

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.

THE ABSORPTION SPECTRUM OF CF2

1967 ◽  
Vol 45 (7) ◽  
pp. 2355-2374 ◽  
Author(s):  
C. Weldon Mathews
Keyword(s):  
Absorption Spectrum ◽  
Electronic State ◽  
Ground State ◽  
Band System ◽  
Electronic States ◽  
Vibrational Structure ◽  
Rotational Structure ◽  
Transition Moment ◽  
High Dispersion ◽  
Parallel Type

The absorption spectrum of CF2 in the 2 500 Å region has been photographed at high dispersion, and the rotational structure of a number of bands has been analyzed. The analysis of the well-resolved subbands establishes that these are perpendicular- rather than parallel-type bands, as previously assigned. Further analysis shows that the upper and lower electronic states are of 1B1 and 1A1symmetries respectively, corresponding to a transition moment that is perpendicular to the plane of the molecule. In the upper electronic state, r0(CF) = 1.32 Å and [Formula: see text], while in the ground state, r0(CF) = 1.300 Å and [Formula: see text]. An investigation of the vibrational structure of the band system has shown that the vibrational numbering in ν2′ must be increased by one unit from earlier assignments, thus placing the 000–000 band near 2 687 Å (37 220 cm−1). A search between 1 300 and 8 500 Å showed two new band systems near 1 350 and 1 500 Å which have been assigned tentatively to the CF2 molecule.

The electronic spectrum of F2

1976 ◽  
Vol 54 (13) ◽  
pp. 1343-1359 ◽  
Author(s):  
E. A. Colbourn ◽  
M. Dagenais ◽  
A. E. Douglas ◽  
J. W. Raymonda
Keyword(s):  
Absorption Spectrum ◽  
Ground State ◽  
Band System ◽  
Rydberg States ◽  
Rotational Analysis ◽  
Interaction Energies ◽  
Rydberg Series ◽  
Rotational Constants ◽  
Vibrational Levels ◽  
Ionic States

The absorption spectrum of F2 in the 780–1020 Å range has been photographed at sufficient resolution to allow a rotational analysis of many bands. A large number of vibrational levels of three ionic states have been observed and their rotational constants determined. Many perturbations in the rotational structure caused by the interaction between the three states have been investigated and the interaction energies determined. The rotational and vibrational structures of a few Rydberg states have also been analyzed in detail but no Rydberg series have been identified. The difficulties in assigning the observed states are discussed. A 1Σu+ – X1Σg+ emission band system has been observed in the 1100 Å region. An analysis of the bands of this system has allowed us to determine the term values and rotational constants of all the vibrational levels of the ground state with ν ≤ 22. The dissociation energy, D0(F2), is found to be greater than 12 830 and is estimated to be 12 920 ± 50 cm−1.

Emission Spectrum of the PO Molecule. Part II.2Σ–2Σ Transitions

1971 ◽  
Vol 49 (24) ◽  
pp. 3180-3200 ◽  
Author(s):  
R. D. Verma ◽  
M. N. Dixit ◽  
S. S. Jois ◽  
S. Nagaraj ◽  
S. R. Singhal
Keyword(s):  
Emission Spectrum ◽  
Ionization Potential ◽  
Dissociation Energy ◽  
Ground State ◽  
Rydberg States ◽  
Electronic States ◽  
Electronic Transitions ◽  
A Value ◽  
Upper Limit ◽  
First Ionization Potential

Rotational structure of emission bands of the PO molecule in the region 5300–3800 Å is analyzed. The spectrum is attributed to 5 electronic transitions A2Σ+–B2Σ+, F2Σ+–B2Σ+, G2Σ+–B2Σ+, H2Σ+–B2Σ+, and I2Σ+–B2Σ+, where F, G, H, and I are the new electronic states and A and B are the upper states of the well-known γ and β bands respectively. Practically all the new 2Σ states are found to be perturbed. A qualitative account of these perturbations together with a deperturbation of certain levels is given. A number of cases of predissociation are also observed. This predissociation is attributed to the presence of 4Πi, and A′2Σ+ states, which dissociate to the ground state atomic products. From this an upper limit of the dissociation energy of the ground state of PO is determined to be D0 = 49 536 cm−1. The A, D, E, G, H, and I states of this molecule are assigned as Rydberg states corresponding to the σ4s, π4p, δ3d, σ4p, σ3d, and σ5s orbitals, respectively. From them a value of 67 570 cm−1 is evaluated for the first ionization potential of PO. All the electronic states established for this molecule are described in terms of electron configurations.

THE PHOTOIONIZATION OF NITROGEN DIOXIDE

1962 ◽  
Vol 40 (6) ◽  
pp. 1064-1067 ◽  
Author(s):  
D. C. Frost ◽  
D. Mak ◽  
C. A. McDowell
Keyword(s):  
Nitrogen Dioxide ◽  
Ionization Potential ◽  
Electron Impact ◽  
Impact Ionization ◽  
Threshold Energy ◽  
Ionization Efficiency ◽  
Efficiency Curve ◽  
Mass Spectrometric Technique ◽  
Measuring Techniques ◽  
First Ionization Potential

The ionization of nitrogen dioxide by photons has been studied using a photoionization mass spectrometric technique and also by the ordinary electron impact method. The photoionization results show a large variation in the relative ionization efficiency within the energy range 9–14 ev, and help to explain the differences between previously reported values for the first ionization potential of this compound. The photoionization efficiency curve indicates the first ionization potential to lie at 9.8 ev and inner ionization potentials to lie at about 11.1 and 12.7 ev.The electron impact ionization efficiency curve for the NO2+ ion exhibits a low ion intensity near the threshold. This confirms the viewpoint that previous determinations of the first ionization potential have employed threshold energy measuring techniques not properly suited for the type of molecule such as nitrogen dioxide which radically changes symmetry on ionization.

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.

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