THE FAR ULTRAVIOLET (C–X) BANDS OF N2+

1956 ◽  
Vol 34 (3) ◽  
pp. 250-255 ◽  
Author(s):  
P. G. Wilkinson

Emission bands of the N2+ C–X system in the vacuum ultraviolet have been obtained under high resolution. The rotational analysis confirms the assignment as a [Formula: see text] transition and the rotational constants obtained are in substantial agreement with previous investigations. The unusual intensity distribution in the ν′ = 3 progression and perturbations in the ν′ = 0, 1, and 2 levels of the C state are in agreement with the theory of inverse predissociation in the ν′ = 3 level.

1970 ◽  
Vol 48 (24) ◽  
pp. 3004-3015 ◽  
Author(s):  
G. Herzberg ◽  
T. J. Hugo ◽  
S. G. Tilford ◽  
J. D. Simmons

The forbidden d3Δi–X1Σ+ transition of CO has been observed in absorption at high resolution in the vacuum ultraviolet region. The intensity distribution in the rotational structure of the observed bands is in conformity with the assumption that the transition occurs on account of the interaction between the d3Δ state and a 1Π state, presumably the A1Π state. Thirteen bands of the d–X system have been analyzed yielding more extensive rotational data for the d3Δi state than were previously known. A discussion of the local perturbations in the d state by the A1Π and a3Π states is included.


1986 ◽  
Vol 64 (6) ◽  
pp. 726-732 ◽  
Author(s):  
B. Coquart ◽  
D. A. Ramsay

Ten bands of the [Formula: see text] system of oxygen have been observed in absorption using longer path lengths than in the earlier work of Herzberg (1953). Rotational analysis of the bands confirms that the A′ 3Δu state is an inverted state as expected from electron-configuration arguments. Rotational assignments are given for the [Formula: see text] and [Formula: see text] sub-bands with ν′ = 2–11; weaker [Formula: see text] sub-bands are identified for ν′ = 5–11. Sub-band origins and rotational constants are given for all the bands. The following derived molecular constants are obtained:[Formula: see text]A comparison of the frequencies of the diffuse bands of oxygen with the sub-band origins of the [Formula: see text] bands shows convincingly that the diffuse bands can be assigned to a weak (O2)2 complex in which one of the O2 molecules is excited to the A′ 3Δu state.


1992 ◽  
Vol 70 (5) ◽  
pp. 291-294 ◽  
Author(s):  
Sheila Gopal ◽  
M. Singh ◽  
G. Lakshminarayana

The emission spectrum of Si130Te was excited by microwave discharge (2450 MHz) in a sealed quartz tube. The A1Π–X1Σ+ band system (3100–3900 Å) (1 Å = 10−10 m) photographed under high resolution on a 10.6 m Ebert grating spectrograph. The rotational analysis of 32 bands was carried out, which led to the determination of the accurate vibrational and rotational constants. The rotational structure belonging to ν′ > 9 levels appear to be perturbed.


1982 ◽  
Vol 60 (12) ◽  
pp. 1730-1742 ◽  
Author(s):  
M. Singh ◽  
M. D. Saksena

Several weak bands of AlO, degraded to the violet and occurring as wide doublets 200 cm−1 apart, have been observed in the region 3300–4000 Å, in emission from a high frequency discharge through a flowing mixture of AlCl3 vapour, oxygen, and argon. These bands have been identified as due to a new electronic transition C2πr–A2πi of AlO. This has been confirmed from a detailed rotational analysis of the 1–0 and 0–1 bands (heads, respectively, at 3481.92, 3506.09 Å and 3683.30, 3710.98 Å) from high resolution spectra. Numerous rotational perturbations have been found in both the C2π3/2 and C2π1/2 substates. Effective rotational constants have been determined for these substates. Λ-doubling has been observed even in the substate C2π3/2.


1988 ◽  
Vol 66 (11) ◽  
pp. 1012-1024 ◽  
Author(s):  
R. Kępa

Seven bands ((0–0) – (0–6)) belonging to the Herzberg system of 13C18O have been recorded in emission using conventional photographic spectroscopy. For the first time, lines of this system have been recorded at high resolution and identified. After the rotational analysis of bands, the rotational constants of the C1Σ+ (ν = 0) and A1Π (ν = 0–6) states, as well as the vibrational constants of the A1Π state, have been determined. A combined analysis of the bands of the Herzberg and Ångström systems have made it possible to determine the constants of the B1Σ+ state more precisely. Numerous rotational perturbations observed in the A1Π state in this isotopic molecule have been analyzed.


2004 ◽  
Vol 82 (6) ◽  
pp. 750-761 ◽  
Author(s):  
A Wüest ◽  
U Hollenstein ◽  
K G de Bruin ◽  
F Merkt

Rotationally resolved (1 + 1′), resonance-enhanced, two-photon ionization spectra of the C 0+u ← X 0+g transition of several isotopomers of Xe2 have been recorded. Rotational constants have been determined for the v′ = 14–26 levels of the C 0+u Rydberg state and the v′′ = 0 and 1 levels of the X 0+g ground state, and band origins have been determined with an absolute accuracy of 0.015 cm–1 for the transitions to the v′ = 14–26 levels of the C 0+u state of the 129Xe2, 129Xe–132Xe, and 131Xe–136Xe isotopomers. The equilibrium internuclear separation of the X 0+g ground state (Re = 4.3773(49) Å) was determined from the rotational constants of the v′′ = 0 and 1 levels. The analysis of the isotopic shifts of the band origins enabled the confirmation of the absolute numbering of the vibrational levels of the C 0+u state determined by Lipson et al. (R.H. Lipson, P.E. Larocque, and B.P. Stoicheff. J. Chem. Phys. 82, 4470 (1985)). A semiempirical interaction potential for the X 0+g ground state was derived in a nonlinear fitting procedure using the present spectroscopic results, the positions of the v′′ = 2–9 levels determined by Freeman et al. (D.E. Freeman, K. Yoshino, and Y. Tanaka. J. Chem. Phys. 61, 4880 (1974)) and experimental values for the second virial coefficient. The interaction potential is similar to previous semiempirical potentials but the dissociation energy (De = (196.1 ± 1.1) cm–1) differs from the value of 183.1 cm–1 determined in the latest ab initio calculation (P. Slavíček, R. Kalus, P. Paška, I. Odvárková, P. Hobza, and A. Malijevský. J. Chem. Phys. 119, 2102 (2003)). Key words: high-resolution vacuum ultraviolet laser spectroscopy, rare gas dimers and their cations, photoionisation, Xe2, rotationally resolved electronic spectrum.


1962 ◽  
Vol 40 (5) ◽  
pp. 586-597 ◽  
Author(s):  
R. D. Verma

The η bands of SiF, in the region 3300–3400 Å, have been photographed in emission at high resolution. A detailed rotational analysis has shown that these bands represent a 4Σ−–2Πτ transition. The lower state is the ground state of the molecule. The principal rotational constants of the upper and lower electronic states in cm−1 are as follows:[Formula: see text]A discussion of the electron configurations is also given.


1969 ◽  
Vol 47 (9) ◽  
pp. 979-994 ◽  
Author(s):  
R. Colin

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.


1974 ◽  
Vol 52 (21) ◽  
pp. 2143-2149 ◽  
Author(s):  
J. Brion ◽  
J. Malicet ◽  
H. Guenebaut

The emission spectrum of the b′3Σu−–X1Σg+ system between 3540–4375 Å and ascribed previously by Mrozowski and Santaram to the a3Σu+–X1Σg+ transition of the P2 molecule, has been photographed under high resolution. The rotational analysis of 7 bands has been carried out and allowed us to determine the rotational constants of the vibrational levels ν′ = 0, 1, and 2 as well as the spin splitting constants λ′ and γ′. The nature of the upper state has been identified as a 3Σu− state, the electronic transition being analogous to the Ogawa–Tanaka–Wilkinson system of N2.


1971 ◽  
Vol 49 (3) ◽  
pp. 317-322 ◽  
Author(s):  
G. N. Currie ◽  
D. A. Ramsay

The 4875 Å band of glyoxal has been photographed in absorption under high resolution and a rotational analysis carried out. The band is of type C and the principal molecular constants are: A′ = 0.9069 cm−1, B′ = 0.1983 cm−1, C′ = 0.1627 cm−1, A″ = 0.8910 cm−1, B″ = 0.2066 cm−1, C″ = 0.1681 cm−1, v0 = 20 507.57 cm−1. The A-rotational constants are smaller by a factor of ~2 than the constants found earlier for trans glyoxal. The new results are consistent with the assignment of the band to an allowed 1B1–1A1 (π*–n) transition of cis glyoxal. Temperature studies indicate that the cis isomer lies 1125 ± 100 cm−1 above the trans isomer. This is the first time that cis glyoxal has been detected experimentally.


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