FORBIDDEN TRANSITIONS IN DIATOMIC MOLECULES: III. NEW AND ABSORPTION BANDS OF THE OXYGEN MOLECULE

1953 ◽  
Vol 31 (4) ◽  
pp. 657-669 ◽  
Author(s):  
G. Herzberg
Keyword(s):  
Diatomic Molecules ◽  
Oxygen Molecule ◽  
Electron Configuration ◽  
Absorption Bands ◽  
Rotational Constants ◽  
Forbidden Transitions ◽  
New Formula

Two new forbidden transitions of the O2 molecule have been found. They give rise to very faint absorption bands overlapping the much stronger forbidden [Formula: see text] bands previously described. The upper states are identified as [Formula: see text] and 3Δu respectively, both of which arise from the same electron configuration as the known states [Formula: see text] and [Formula: see text]. For the [Formula: see text] state the following vibrational and rotational constants have been determined: Te = 36678.91, ωe = 650.49, ωexe = 17.036, ωeye = −0.1056, ωeze = −0.00744, Be = 0.8261, αe = 0.0205, γe = −0.000830 cm.−1, γe = 1.597 × 10−5 cm. The constants are based on the assumption of a certain vibrational numbering which may have to be revised (increased). For the 3Δu state the data are quite fragmentary and only two rotational constants, B5 = 0.8177, B6 = 0.7915, and one vibrational quantum, [Formula: see text], have been determined. The bands of the [Formula: see text] system are very close to those of the [Formula: see text] system and represent in all probability the analogue in free O2 of the diffuse triplet bands of Wulf, Finkelnburg, and Steiner ascribed to O4. The positions of the new [Formula: see text] and 3Δu states agree closely with those predicted by Moffitt. Almost half of the unidentified features of the spectrum of the nightglow agree within 5 Å with the predicted positions of emission bands of the [Formula: see text] system.

FORBIDDEN TRANSITIONS IN DIATOMIC MOLECULES: IV. THE a′3Σ+ ← XlΣ+ AND e3Σ− ← X1Σ+ ABSORPTION BANDS OF CARBON MONOXIDE

1955 ◽  
Vol 33 (12) ◽  
pp. 757-772 ◽  
Author(s):  
G. Herzberg ◽  
T. J. Hugo
Keyword(s):  
Carbon Monoxide ◽  
Diatomic Molecules ◽  
Electronic Transitions ◽  
Absorption Bands ◽  
Unusual Structure ◽  
Precise Data ◽  
Forbidden Transitions ◽  
Perturbation Data ◽  
Vibrational Constants ◽  
Heteronuclear Molecules

Two examples of forbidden electronic transitions in heteronuclear molecules, 3Σ+ – 1Σ+ and 3Σ− – 1Σ+, are studied in the spectrum of the CO molecule. The bands have been obtained in absorption in the region 1750 to 1230 Å with absorbing paths up to 400 cm-atm., using the fourth and fifth orders of a 3 meter vacuum spectrograph. In most of the 3Σ+ – 1Σ+ bands all four predicted branches are observed. For the 3Σ− – 1Σ+ bands, a somewhat unusual structure is predicted: two branches of O and S form and three branches of Q form. In the best-resolved bands, four branches are observed which closely fit the predicted branches, two of the Q branches being very nearly coincident and unresolved in the present spectra. The rotational and vibrational constants of the upper states, a′3Σ+ and e3Σ− of the two band systems have been determined. Some of these data had previously been obtained from perturbations in other band systems of CO. On the whole, the perturbation data agree satisfactorily with the more precise data obtained directly in the present study.

Vibration-rotation bands and rotational constants of dideuteroacetylene

1955 ◽  
Vol 232 (1190) ◽  
pp. 291-309 ◽  
Keyword(s):  
Resolving Power ◽  
Vibrational States ◽  
Absorption Bands ◽  
Rotational Constants ◽  
Vibrational Assignments ◽  
Vibrational Anharmonicity ◽  
A Value ◽  
Vibrational Levels ◽  
Vibration Rotation ◽  
Very High

Nine vibrational absorption bands of dideutero-acetylene have been examined with very high resolving power. The rotational constants have been determined for the vibrational levels concerned, and the coefficients α i have been determined with more convincing accuracy than previously. In some of the bands the Q branches have been resolved, so that the l -doubling coefficients q i could be derived, and details could be established about the doublet components in some II levels. The results emphasize the need of high resolution if the vibrational assignments are to be unambiguous, and if reliable values of the rotational constants are to be derived. A value of B e has been obtained, and the vibrational anharmonicity coefficients have been considered briefly. Estimates of the centrifugal stretching constants D i in different vibrational states have been made, and one anomalous case has been found.

NEW ELECTRONIC TRANSITIONS OF THE BH MOLECULE

1941 ◽  
Vol 19a (2) ◽  
pp. 27-31 ◽  
Author(s):  
A. E. Douglas
Keyword(s):  
Electronic Transitions ◽  
Lower State ◽  
Electron Configuration ◽  
Rotational Constants ◽  
Boron Trichloride ◽  
New States ◽  
Π State

In a discharge in helium with a trace of boron trichloride and hydrogen three new bands are found at 3415 Å, 3396 Å, and 3099 Å. Measurements of these bands show that they are due to two new electronic transitions of the BH molecule. The upper states of both transitions are previously unknown 1Σ+ states. The lower state of both transitions is the same and is a known 1Π state. The rotational constants of both new states have been determined and their electron configuration is suggested.

scholarly journals High Resolution Spectroscopy With Molecular Beams and Tunable Lasers

1998 ◽  
Vol 18 (1-2) ◽  
pp. 1-11 ◽  
Author(s):  
R. Vetter ◽  
P. Luc ◽  
C. Amiot
Keyword(s):  
Electronic Structure ◽  
High Resolution ◽  
Diatomic Molecules ◽  
Reaction Dynamics ◽  
Molecular Beams ◽  
Tunable Lasers ◽  
High Resolution Spectroscopy ◽  
Absorption Bands ◽  
Quantum Numbers ◽  
Laser Techniques

High resolution Doppler-free laser techniques are used in beam experiments to improve the spectroscopic description of complex diatomic molecules. The case of TiO is considered here for its implication in reaction dynamics studies and its interest in Astrophysics. Two absorption bands in the visible have been analyzed: B3Π−X3 Δ(1−0) and c1Φ−a1 Δ(0−0). Owing to accurate wavenumber measurements, it has been possible to extend the analysis to high rotational quantum numbers and to carry out detailed spectroscopic calculations. They show that a careful revisiting of the TiO electronic structure is necessary.

The electronic spectra of osmium and ruthenium tetroxides

1967 ◽  
Vol 20 (11) ◽  
pp. 2315 ◽  
Author(s):  
EJ Wells ◽  
AD Jordan ◽  
DS Alderdice ◽  
IG Ross
Keyword(s):  
Electronic Spectra ◽  
Detailed Structure ◽  
Absorption Bands ◽  
Forbidden Transitions

The spectrum of OsO4 has been measured in the vapour and in solution. Detailed structure reported in the main absorption bands by Langseth and Qviller was not reproduced. The irregularity of the main intervals between peaks, and their sensitivity to temperature, bespeak a perturbed spectrum which is too diffuse to analyse convincingly. Three fragmentary systems of quite different appearance were observed in all samples and could well be weak forbidden transitions. The spectrum of RuO, vapour is no better resolved. Reproducible features of both spectra are tabulated.

High-resolution studies of the near-ultraviolet bands of oxygen: III: the system

1986 ◽  
Vol 64 (6) ◽  
pp. 726-732 ◽  
Author(s):  
B. Coquart ◽  
D. A. Ramsay
Keyword(s):  
High Resolution ◽  
Electron Configuration ◽  
Rotational Analysis ◽  
Molecular Constants ◽  
Rotational Constants ◽  
Near Ultraviolet ◽  
Path Lengths

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.

BAND SPECTRUM AND STRUCTURE OF THE BCl MOLECULE

1941 ◽  
Vol 19a (11) ◽  
pp. 127-137 ◽  
Author(s):  
G. Herzberg ◽  
W. Hushley
Keyword(s):  
Fine Structure ◽  
Internuclear Distance ◽  
Ground State ◽  
Vibrational Structure ◽  
Sixth Order ◽  
Band Spectrum ◽  
Molecular Constants ◽  
Rotational Constants ◽  
New Formula

The 1Π−1Σ+ system of the BCl molecule has been photographed in the sixth order of a 20 ft. grating. The previous interpretation of the vibrational structure by Miescher (5) is slightly modified. The new formula for the Q heads of the B11Cl35 molecule is[Formula: see text]The fine structure of a number of bands has been measured and analysed, leading to the following accurate values for the rotational constants: B′e = 0.7054 cm.−1, α′e = 0.00820 cm.−1, B″e = 0.6838 cm.−1, α″e = 0.00646 cm.−1. The internuclear distance in the ground state is r″e = 1.716.10−8 cm. The molecular constants of BCl are compared with those of the iso-electronic molecules CS, PN, and SiO as well as with those of BBr, BCls, and BBr3.

Vibration-rotation bands and molecular constants of carbonyl sulphide

1954 ◽  
Vol 222 (1151) ◽  
pp. 431-443 ◽  
Keyword(s):  
Fermi Resonance ◽  
Resolving Power ◽  
Molecular Constants ◽  
Absorption Bands ◽  
Coriolis Interaction ◽  
Rotational Constants ◽  
Vibrational Levels ◽  
Vibration Rotation ◽  
Carbonyl Sulphide ◽  
First Time

The vibrational absorption bands of carbonyl sulphide 12 C 16 O 33 S near 5 μ have been examined using very high resolving power. Rotational fine structure has been resolved for the first time; six bands have been studied, including two associated with the isotopic species 13 C 16 O 33 S, and a rotational analysis of each has been carried out. Values have been derived for the rotational constants B and D in the different vibrational levels, and these have been compared with the results obtained from the microwave spectrum for the lower states. It has been found that the location of certain bands, and the rotational constants B are affected by Fermi resonance and Coriolis interaction, and estimates of the unperturbed values have been made.

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