The absorption spectrum of gaseous hydrogen bromide in the schumann region I. Rotational analysis

1961 ◽  
Vol 263 (1313) ◽  
pp. 259-276 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Hydrogen Bromide ◽  
Electronic States ◽  
Gaseous Hydrogen ◽  
Rotational Structure ◽  
Resolving Power ◽  
Rotational Analysis ◽  
Region I

The absorption spectrum of gaseous hydrogen bromide has been photographed in the region 1180 to 1500 Å, using fourth and fifth orders of a 3 m grating. About forty bands have been observed. The resolving power sufficed for the study of most of the discrete rotational structure. The analysis reveals that few of the bands are related in vibrational progressions and shows rather that they are to be associated with atleast thirty new electronic states.

The absorption spectrum of gaseous hydrogen bromide in the Schumann region - II. Electronic states

1961 ◽  
Vol 263 (1313) ◽  
pp. 277-288 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Excited States ◽  
Hydrogen Bromide ◽  
Electronic States ◽  
Orbit Interaction ◽  
Gaseous Hydrogen ◽  
Spin Orbit ◽  
Absorption Bands ◽  
Atomic Orbitals ◽  
Region Ii

The electronic states of HBr are discussed. The large number of states observed in the region 8·2 to 10·4 eV (part I) arise by the addition of an electron to the HBr + ( X 2 II i ) core. These are ‘highly excited’ states in which molecular orbitals derived from excited atomic orbitals are occupied. Coupling cases similar to those shown in the highly excited states of H 2 and of He 2 are envisaged, but the situation in HBr is complicated by the orbital angular momentum of the HBr + ion and by spin-orbit interaction. It is suggested that these coupling cases give rise to the unusual rotational structures observed in some of the absorption bands.

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.

scholarly journals The spectrum of rubidium hydride, RbH I. Analysis

1939 ◽  
Vol 173 (952) ◽  
pp. 28-37 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Electronic Transition ◽  
Rotational Constant ◽  
Rotational Structure ◽  
Rotational Analysis ◽  
The Many ◽  
Sodium And Potassium ◽  
Line Type ◽  
Overlapping Bands

The spectra of the diatomic hydrides of lithium, sodium and potassium have been studied both in absorption and in emission by several authors, LiH by Nakamura (1930, 1931) and Crawford and Jorgensen (1935), NaH by Hori (1930, 1931) and Olsson (1935), KH by Almy and Hause (1932) and Hori (1933), and recently Almy and Rassweiler (1938) have published details of the absorption spectrum of caesium hydride. All these hydrides show spectra of the “ many-line” type consisting of numerous overlapping bands with open rotational structure and no obvious heads. A rotational analysis shows that they all have the same type of electronic transition, 1Σ → 1Σ ,and are very strongly degraded towards the red. These spectra are all anomalous in that the frequency, ω´ v , and the rotational constant, B'v,increase at first with increasing initial vibrational quantum numbe v `.

Vibration-rotation bands of allene

1949 ◽  
Vol 200 (1060) ◽  
pp. 1-9 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Geometrical Structure ◽  
Rotational Structure ◽  
Resolving Power ◽  
Vibrational Absorption ◽  
Grating Spectrometer ◽  
Fundamental Frequencies ◽  
Coriolis Perturbation ◽  
Vibration Rotation

The vibrational absorption spectrum of allene has been reinvestigated using a new grating spectrometer of high resolving power. The rotational structure of many of the bands has been measured and discussed in relation to the geometrical structure of the molecule. The perpendicular-type bands associated with absorption of the fundamental frequencies of degenerate oscillations show features of particular interest. Two of these bands provide an elegant example of a type of Coriolis perturbation originally predicated by Nielsen, and which results in an unusual arrangement of the Q branches in each band.

THE ABSORPTION SPECTRUM OF CNC

1966 ◽  
Vol 44 (2) ◽  
pp. 353-372 ◽  
Author(s):  
A. J. Merer ◽  
D. N. Travis
Keyword(s):  
Absorption Spectrum ◽  
Bond Length ◽  
Ground State ◽  
Flash Photolysis ◽  
Electronic States ◽  
Electronic Transitions ◽  
Ultraviolet Absorption Spectrum ◽  
Rotational Analysis ◽  
Bending Vibrations ◽  
Show Evidence

The ultraviolet absorption spectrum of the free CNC radical has been discovered in the flash photolysis of diazoacetonitrile, HC(CN)N2. The identity of the radical has been proved from isotopic evidence, using 15N and 13C, together with rotational analysis of the bands. Rotational analyses have shown that the bands of CNC must be assigned to two electronic transitions, A2Δu–X 2Πg, and [Formula: see text]. The sequence bands in the bending vibrations, which are observed in both electronic transitions, show evidence of Renner–Teller interaction in both the degenerate electronic states: this interaction is extremely large in the X2Πg state. The principal constants (in cm−1) of the observed states of CNC are as follows:[Formula: see text]The C—N bond length in the ground state of CNC is found to be 1.245 Å.CNC is isomeric with CCN, whose spectrum has been reported previously; some interesting comparisons are made between the spectra of these two molecules.

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).

Rotational Analysis of the A–X System of the SiCl Molecule

1971 ◽  
Vol 49 (4) ◽  
pp. 407-411 ◽  
Author(s):  
S. R. Singhal ◽  
R. D. Verma
Keyword(s):  
Ground State ◽  
Electronic States ◽  
Rotational Structure ◽  
Spin Coupling ◽  
Quartz Tube ◽  
Rotational Analysis ◽  
Coupling Constant ◽  
Spin Coupling Constant ◽  
Molecular Constants ◽  
Vibrational Levels

The A–X system of the SiCl molecule in the region 4500–6400 Å has been excited by an r.f. discharge through a mixture of argon and a trace of SiCl4 vapor, flowing through a quartz tube. Several red degraded and double headed bands with ν′ = 0, 1, 2, and 3 have been observed and the rotational structure of the 0-5, 0-6, 0-7, 0-8, 0-9, 0-10, 1-9, and 1-10 bands has been analyzed. The analysis shows that the bands arise from a 2Σ–2Π transition, 2Π being the ground state of the molecule. The molecular constants have been determined for both the electronic states. The spin coupling constant, Aν, of the X2Π vibrational levels has been found to follow an equation[Formula: see text]

Vibration-rotation bands of allene-1 . 1- d 2

1959 ◽  
Vol 250 (1260) ◽  
pp. 39-52 ◽  
Keyword(s):  
Raman Spectrum ◽  
Rotational Structure ◽  
Resolving Power ◽  
Geometrical Parameters ◽  
Rotational Analysis ◽  
Coriolis Interaction ◽  
A Value ◽  
Vibration Rotation ◽  
Parallel Type

The spectrum of allene-1 . 1- d 2 in the range 3 to 20 μ has been measured using high resolving power. An analysis of several parallel-type bands has given values for B 0 which agree closely with that obtained from the rotational Raman spectrum (0∙2619 cm –1 ). In assigning the perpendicular bands to particular vibrations, some characteristic details of their rotational structure arising from the slight asymmetry have been taken into account. From a rotational analysis of four perpendicular bands it has been possible to derive a value for ( A 0 ─ B 0 ), from which A 0 is obtained. Using B 0 values for allene, allene- d 2 and allene- d 4 , and the new value for A 0 of allene- d 2 , the geometrical parameters have been calculated, namely, r 0 CH = 1∙080 Å, r 0 cc = 1∙308 Å, and ∠HCH = 119°. Some of the perpendicular bands at longer wavelengths illustrate a special type of Coriolis interaction between B 1 and B 2 class vibrations, and the results are in general accord with Nielsen’s theory of this effect.

Rotational Structure in the A2Σ+, B2Σ+, and a4Σ− – X2Π Transitions of GeF

1973 ◽  
Vol 51 (2) ◽  
pp. 125-143 ◽  
Author(s):  
R. W. Martin ◽  
A. J. Merer
Keyword(s):  
Matrix Element ◽  
Ground State ◽  
Electronic States ◽  
Second Order ◽  
Rotational Structure ◽  
Rotational Analysis ◽  
Rotational Constants ◽  
Intensity Enhancement ◽  
Perturbation Matrix

Rotational analysis of over 50 sub-bands of three emission transitions of 74GeF has given vibrational and rotational constants for the four lowest-lying electronic states of GeF. One of these is a 4Σ− state in Hund's case (a), where all four spin components have been identified. Extensive perturbations between this 4Σ− state and the B2Σ+ state have been analyzed in detail: the two states appear to interact mainly by a second-order mechanism through the so far uncharacterized σπ22Σ+ state, but the surprisingly large J dependence of the perturbation matrix element suggests that another mechanism, possibly involving the ground state, may contribute. Further perturbations, where the lines show an unusual intensity enhancement, appear in those sub-bands with B2Σ+ ν = 4 as upper state.

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.

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