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.

ROTATIONAL ANALYSIS OF THE β BANDS OF PHOSPHORUS MONOXIDE

1959 ◽  
Vol 37 (2) ◽  
pp. 136-143 ◽  
Author(s):  
Nand Lal Singh
Keyword(s):  
Ground State ◽  
Band System ◽  
Electronic States ◽  
Rotational Analysis ◽  
Rotational Constants ◽  
Fine Structures ◽  
Π State

The fine structures of three of the β bands of PO which occur near 3200 Å have been analyzed. The analysis shows that the upper state of this band system is a 2Σ and not a 2Π state as previously believed. The rotational constants of both electronic states have been determined and it is found that the ground state constants, previously determined from the γ bands, are incorrect.

The electronic spectrum of the CS+ molecular ion: rotational analysis and perturbation effects in the A2Πi–X2Σ+ transition

1978 ◽  
Vol 56 (5) ◽  
pp. 587-600 ◽  
Author(s):  
D. Gauyacq ◽  
M. Horani
Keyword(s):  
Carbon Disulfide ◽  
Ground State ◽  
Valence Electron ◽  
Band System ◽  
Local Perturbation ◽  
Rotational Analysis ◽  
Molecular Constants ◽  
Molecular Ion ◽  
Vibrational Levels ◽  
The Difference

A new emission spectrum in the red region (6000–8000 Å) has been recorded from a low pressure hot cathode discharge through carbon disulfide. This band system has been assigned to the A2Πi–X2Σ+ transition of the CS+ molecular ion on the basis of the rotational analysis and comparison with other nine valence-electron molecules. Molecular constants have been obtained by direct least squares fits of the line frequencies to the difference of the eigenvalues of standard 2Π and 2Σ+ matrices.A local perturbation in the A2Πi (ν = 5) state has been studied quantitatively. The position of the perturbing vibrational level in the X2Σ+ state has been determined within a few centimetre−1. This study gave a consistent set of molecular constants for the ground state of CS+ and allowed a partial deperturbation treatment of the observed vibrational levels of the excited A2Πi state.Numerous bands are also observed in the 4000 Å region. A discussion is given concerning the possible assignment of bands at 4059 and 4110 Å to the CS+B2Σ+–A2Πi (0,0) transition.

Rotational analysis of the A0 + , B0 + ← X 1 Ʃ + systems of gaseous AgF

1971 ◽  
Vol 322 (1549) ◽  
pp. 243-249 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Dissociation Energy ◽  
Ground State ◽  
Rotational Structure ◽  
Rotational Analysis ◽  
Vibrational Levels

The absorption spectrum of AgF in the region 300.0 to 355.0 nm consists of a continuum centred at about 303.0 nm and two-band systems, A0 + , and B0 + ← X 1 Ʃ + . Rotational analyses have been made for all seven bands observed in the A─X system and of four bands in the B─X system, for both 107 AgF and 109 AgF. State A seems to have a very low dissociation energy and may possess only two stable vibrational levels. Lines at high J appear diffuse, indi­cating predissociation, perhaps by rotation. State B is also predissociated and only the bands with v ' ═ 0 show sharp rotational structure. The predissociating state is probably an Ω ═ 1 state which is the upper state of the 303.0 nm continuum. Constants for the ground state of 107 AgF are as follows: G v ═ 513.447 ± 0.009 ( v + ½) ─ 2.593 ± 0.002 ( v + ½) 2 B v ═ 0.26567 ─ 0.001901± 8 ( v + ½).

Spectrum of SO: Analysis of the B3Σ−–X3Σ− and A3 Π–X3Σ− band systems

1969 ◽  
Vol 47 (9) ◽  
pp. 979-994 ◽  
Author(s):  
R. Colin
Keyword(s):  
Absorption Spectrum ◽  
High Resolution ◽  
Microwave Discharge ◽  
Flash Photolysis ◽  
Band System ◽  
Rotational Analysis ◽  
Rotational Constants ◽  
Π State

The absorption spectrum of SO radicals produced by flash photolysis of a mixture of COS + O2 + Ar is investigated. A partial rotational analysis of the previously known bands of the B3Σ−–X3Σ− transition which lie in the region of 1900 to 2400 Å is presented, and the predissociations and perturbations of the B3Σ−state are discussed. A complex red-degraded band system near 2500 Å, previously observed in emission and attributed to SO2, is shown to be due to a 3Π–X3Σ− transition of the SO molecule. Effective rotational constants of the 3Π state are derived from the analysis of these bands photographed at high resolution. In order to obtain the vibrational numbering of the 3Π–X3Σ− bands, these were also photographed in emission from a microwave discharge through a mixture of S18O2 + S16O2. A general discussion of the currently known states of the SO molecule is given.

Rotational Analysis of the Absorption Spectrum of Heavy Oxygen (18O2) in the Region 1200–1285 Å

1975 ◽  
Vol 53 (24) ◽  
pp. 2703-2711 ◽  
Author(s):  
Masaru Ogawa
Keyword(s):  
Absorption Spectrum ◽  
Rydberg States ◽  
Normal Incidence ◽  
Rotational Constant ◽  
Electron Configuration ◽  
Rotational Analysis ◽  
Rotational Constants ◽  
Strong Band

The absorption spectrum of 18O2 has been photographed with a 6.65 m normal incidence type vacuum spectrograph in the 1070–1300 Å region. Rotational structures of the following bands have been analyzed; 1–0, 2–0, 3–0, and 4–0 of α1Σu+ ← X3Σg−; 2–0and 3–0 of β3Σu+ ← X3Σg−; and a strong band at 1246 Å. The upper state of the 1246 Å band is determined to have 3Σu− symmetry, and the transition is designated E3Σu− ← X3Σg−. These three upper states are Rydberg in character, with electron configuration (πu2p)4(πg2p)(3pπ). The observed rotational constants of the α1Σu+ and β3Σu+ states are nearly identical to those of the X2Πg state of O2+ to which these three Rydberg states converge. However, the rotational constant of the E3Σu− state, B1 = 1.3702 cm−1, is much smaller than the value B1 = 1.4764 cm−1 for the X2Πg state of 18O2+ estimated from the corresponding 16O2+ value. A brief discussion of this discrepancy is given.

ABSORPTION SPECTRUM OF THE NO MOLECULE: VI. BAND STRUCTURES BELOW 1 600 Å, RYDBERG STATES C2Π, D2Σ+, K2Π, M2Σ+, S2Σ+, NON-RYDBERG STATES B2Π, L2Π AND THEIR INTERACTIONS

1966 ◽  
Vol 44 (7) ◽  
pp. 1525-1539 ◽  
Author(s):  
A. Lagerqvist ◽  
E. Miescher
Keyword(s):  
Absorption Spectrum ◽  
Electronic State ◽  
Fourth Order ◽  
Rydberg States ◽  
Liquid Oxygen ◽  
Interaction Energies ◽  
Band Structures ◽  
Vibrational Levels ◽  
Π State ◽  
Potential Curves

The study of the absorption spectrum of the NO molecule has been continued on plates taken in the fourth order of a 10.5-m vacuum spectrograph. The spectra of 14N16O, 15N16O, 14N18O, and 15N18O gases, each kept at liquid-oxygen temperature, were photographed separately. Rotational analyses were carried out for many bands observed below 1 600 Å. Constants for levels of the Rydberg complexes 3p, 4s, 4p, and 5s have been derived. These levels include ν = 5 and ν = 6 of the C2Π state, levels that interact with the levels ν = 21 and 24 respectively of the configurationally different B2Π state. It is shown that the vibrational levels, now well established above the energy where the potential curves of the C and B states cross, are to be attributed to "crossing" curves.The level ν = 4 of the L2Π state, which was discerned in the spectra of the heavier isotopes only, coincides in 14N16O with the level ν = 6 of C2Π and produces a strong three-level perturbation. The level, perturbed in this way, has the appearance of a separate electronic state in 14N16O and at one time was so identified.Many interaction energies are determined, and the new systems of "deper-turbed" levels are thoroughly discussed.

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 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 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.

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