New results on the D2Π and B′2Π states of the PO molecule

1976 ◽  
Vol 54 (6) ◽  
pp. 695-708 ◽  
Author(s):  
S. Ghosh ◽  
S. Nagaraj ◽  
R. D. Verma
Keyword(s):  
Absorption Spectrum ◽  
High Resolution ◽  
Vibrational Level ◽  
Rotational Analysis ◽  
X Band ◽  
Vibrational Levels ◽  
Π State

A rotational analysis of the D–X and D′–X band systems of PO in the region 1900–2100 Å has been reinvestigated from an absorption spectrum taken at high resolution. A new ν = 1 vibrational level of the D2Π state of PO interacting with a new vibrational level of the D′2Π state has been studied in detail. Two other new vibrational levels, ν = 2 and 3, of D2Π have been recorded and studied in detail. A rigorous deperturbation of the D and D′ levels has been carried out. It has been shown that D′2Π and B′2Π are one and the same state of the PO molecule. A new band overlapped by the D′–X, 26–0 band has been attributed to the B2Σ+–X2Π transition.

The A2Π–X2Σ+ system of MgCl

1987 ◽  
Vol 65 (12) ◽  
pp. 1594-1603 ◽  
Author(s):  
M. Singh ◽  
G. S. Ghodgaonkar ◽  
M. D. Saksena
Keyword(s):  
High Resolution ◽  
Structure Analysis ◽  
Vibrational Level ◽  
High Frequency ◽  
Low Frequency ◽  
Rotational Structure ◽  
Rotational Analysis ◽  
The Common ◽  
Π State

The A2Π–X2Σ+ system of MgCl has been photographed at high resolution and analyzed for the rotational structure. Analysis of the low-frequency sub-bands of the 0–0, 0–1, and 0–2 bands showed that there is a nonzero Λ doubling in the common vibrational level ν′ = 0, thereby indicating that the A2Π state is regular and not inverted as presumed by earlier workers. Spin-doubling has been seen in the ν = 1 and 2 levels of the X2Σ+ state. Rotational analysis of the high-frequency sub-band has also been done for the 0–0 band.

The absorption spectrum of C2H2 around ν1 + ν3: energy standards in the 1.5 μm region and vibrational clustering

1994 ◽  
Vol 72 (11-12) ◽  
pp. 1241-1250 ◽  
Author(s):  
Q. Kou ◽  
G. Guelachvili ◽  
M. Abbouti Temsamani ◽  
M. Herman
Keyword(s):  
Absorption Spectrum ◽  
Fourier Transform ◽  
High Resolution ◽  
Rotational Analysis ◽  
Vibrational Assignment ◽  
Calibration Standards ◽  
Vibrational Levels ◽  
Vibrational Transitions ◽  
The Fourier Transform ◽  
Anharmonic Couplings

We have recorded the Fourier transform absorption spectrum of acetylene, C2H2, at high resolution, around 6500 cm−1. The positions of the strongest rovibrational lines are measured with respect to the rovibrational lines in 3-0 of CO. They provide secondary calibration standards in that range with an accuracy of 3 × 10−4 cm−1. The rotational analysis of the data gives evidence of five vibrational levels of [Formula: see text] symmetry, in addition to the bright combination level (1010000). This is demonstrated to strictly fit the predicted anharmonic resonance pattern in that region, which permits the vibrational assignment of those extra transitions. Study of the relative intensities of the reported vibrational transitions suggests the need to include new quartic anharmonic couplings. This is supported by the rovibrational analysis of the cold bands around 8500 cm−1, involving the (1110000) bright level, which is also presented.

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.

STRUCTURE OF THE BAND SPECTRUM OF CuCl MOLECULE: II. ROTATIONAL STRUCTURE OF THE F–X BAND SYSTEM OF Cu65Cl35

1962 ◽  
Vol 40 (4) ◽  
pp. 412-422 ◽  
Author(s):  
P. Ramakoteswara Rao ◽  
R. K. Asundi ◽  
J. K. Brody
Keyword(s):  
High Resolution ◽  
Electronic Transition ◽  
Band System ◽  
Rotational Structure ◽  
Band Spectrum ◽  
Rotational Analysis ◽  
Molecular Constants ◽  
X Band ◽  
Π State

The F–X band system of Cu65Cl35 extending from 3700 to 4200 Å has been photographed in emission under high resolution. Rotational analysis of the (3,0), (2,0), (1,0), (0,0), (0,1), and (0,2) bands of the system has been made. The electronic transition involved is found to be 1Π–1Σ. The Λ-type doubling in the 1Π state is negligible. The principal molecular constants obtained are as follows (cm−1 units)[Formula: see text]

THE LYMAN BANDS OF MOLECULAR HYDROGEN

1959 ◽  
Vol 37 (5) ◽  
pp. 636-659 ◽  
Author(s):  
G. Herzberg ◽  
L. L. Howe
Keyword(s):  
High Resolution ◽  
Vibrational Level ◽  
Ground State ◽  
Molecular Hydrogen ◽  
Equilibrium Constants ◽  
Dissociation Limit ◽  
Vibrational Levels ◽  
State Formula ◽  
Single Formula ◽  
Vibrational Constants

The Lyman bands of H2 have been investigated under high resolution with a view to improving the rotational and vibrational constants of H2 in its ground state. Precise Bv and ΔG values have been obtained for all vibrational levels of the ground state. One or two of the highest rotational levels of the last vibrational level (v = 14) lie above the dissociation limit. Both the [Formula: see text] and ΔG″ curves have a point of inflection at about v″ = 3. This makes it difficult to represent the whole course of each of these curves by a single formula and therefore makes the resulting equilibrium constants somewhat uncertain. This uncertainty is not very great for the rotational constants for which we find[Formula: see text]but is considerable for the vibrational constants ωe and ωexe for which three-, four-, five-, and six-term formulae give results diverging by ± 1 cm−1. The rotational and vibrational constants for the upper state [Formula: see text] of the Lyman bands are also determined. An appreciable correction to the position of the upper state is found.

High-resolution laser-excitation spectrum of the A2Π ← X2Σ system of TiN: rotational analysis of the 0–0, 1–1, and 2–2 bands

1985 ◽  
Vol 63 (7) ◽  
pp. 997-1004 ◽  
Author(s):  
K. Brabaharan ◽  
J. A. Coxon ◽  
A. Brian Yamashita
Keyword(s):  
High Resolution ◽  
Least Squares ◽  
Excitation Spectrum ◽  
Laser Excitation ◽  
Rotational Analysis ◽  
Molecular Constants ◽  
Individual Bands ◽  
Measured Line ◽  
Line Positions ◽  
Π State

The 0–0, 1–1, and 2–2 bands of the A2Π ← X2Σ system of TiN have been recorded using the technique of laser-excitation spectroscopy. Molecular constants have been obtained from direct least squares fits of the measured line positions of individual bands. The fitted constants confirm and extend previous determinations; for the A2Π state, some of the constants show unusually large variations with ν, in accord with the already known perturbation of this state in the ν = 0 level.

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.

The 7500 to 4500 Å absorption system of the free HCO radical

1955 ◽  
Vol 233 (1192) ◽  
pp. 34-54 ◽  
Keyword(s):  
Absorption Spectrum ◽  
High Resolution ◽  
Flash Photolysis ◽  
Lower State ◽  
Absorption System ◽  
Molecular Plane ◽  
Bending Mode ◽  
Vibrational Levels ◽  
Other Substances ◽  
Low Dispersion

A fairly extensive absorption spectrum o f the free HCO radical produced by flash photolysis of acetaldehyde and other substances has been investigated with long absorbing paths and under high resolution. The corresponding DCO spectrum has also been studied. The absorption spectrum consists of simple bands with P, Q and R branches. It is shown that the molecule is linear in the upper state, but bent in the lower state with an angle of about 120° and a CO bond length of approximately 1.20 Å. Rotational constants of HCO and DCO in both upper and lower states have been derived. Various arguments based on the high-resolution measurements lead to the conclusion that the main progression of bands corresponds to transitions to the vibrational levels of the upper state with even v' 2 (the vibrational quantum number of the bending mode). This conclusion is confirmed by the observation under low dispersion of some of the intermediate bands with odd v’ 2 which are diffuse and therefore not easily recognizable under high resolution. Apparently all levels of the upper state with l≠0 are predissociated. The type of the electronic transition is shown to be 2 Σ+ ← 2 A”, that is, the transition moment is perpendicular to the molecular plane. The lower state cannot arise from normal CO and H.

High resolution absorption spectrum of nitric oxide (NO) in the region of the first ionization limit

1976 ◽  
Vol 54 (20) ◽  
pp. 2074-2092 ◽  
Author(s):  
E. Miescher
Keyword(s):  
Absorption Spectrum ◽  
High Resolution ◽  
Ionization Energy ◽  
Dissociation Limit ◽  
Matrix Elements ◽  
Rydberg Series ◽  
Isotopic Species ◽  
Vibrational Levels ◽  
Energy Formula ◽  
Ionization Limit

The absorption spectrum of cold NO gas has been photographed at high resolution between 1400 and 1250 Å for two isotopic species. Resolved bands of the Rydberg series converging to vibrational levels of the 1Σ+ ground state of NO+ are studied. They include nf–X bands up to n = 15 and ns–X bands up to n = 11, all of which show sharp rotational structure. The higher members of the np–X series are generally very diffuse with only npσ being sufficiently sharp to show broadened rotational lines. Also mostly diffuse are the ndδ–X bands. The bands ndσ, π–X are not observed. The rapidly (n−3) narrowing structure of the nf complexes is discussed and the ionization energy [Formula: see text] accurately determined by extrapolation of selected rotational lines. Interactions between Rydberg states are numerous, s ~ d mixing produces a strong effect above n = 6 when (n + 1)s levels fuse with nl levels into 'supercomplexes'. Matrix elements are given for observed 8f ~ 9s and 6f ~ 6dδ interactions.Valence levels are not observed above the ionization energy, except for the repulsive state A′2Σ+ arising from the first dissociation limit and seemingly assuming Rydberg character at molecular internuclear distance. Observed anomalies are qualitatively discussed.

Emission Spectrum of the PO Molecule. Part III. Spectrum in the Red Region

1972 ◽  
Vol 50 (13) ◽  
pp. 1579-1586 ◽  
Author(s):  
S. Guha ◽  
S. S. Jois ◽  
R. D. Verma
Keyword(s):  
Emission Spectrum ◽  
Structure Study ◽  
Rotational Structure ◽  
Rotational Analysis ◽  
Vibrational Levels ◽  
Π State

Four new bands in the red region are observed which have been described in terms of A2Σ+–B2Σ+ and F2Σ+–B2Σ+ systems. A rotational analysis together with deperturbation calculation of one band at 6763 Å has shown that A2Σ+ (ν = 7) and F2Σ+ (ν = 0) vibrational levels are involved in a homogeneous perturbation. The rotational structure study of three bands of a new transition I2Σ+–A2Σ+ has been carried out. From the study of heterogeneous perturbations observed in the I vibrational levels, it has been suggested that the perturbing state is a 2Π state arising from the 3d complex.

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