The Electronic Spectrum of HF. I. The B1Σ+–X1Σ+ Band System

1973 ◽  
Vol 51 (4) ◽  
pp. 434-445 ◽  
Author(s):  
G. Di Lonardo ◽  
A. E. Douglas
Keyword(s):  
Absorption Spectrum ◽  
High Resolution ◽  
Emission Spectrum ◽  
Electronic Spectrum ◽  
Dissociation Energy ◽  
Band System ◽  
Vibrational Levels ◽  
Internuclear Distances ◽  
X State ◽  
Potential Curves

The electronic emission and absorption spectrum of HF has been photographed at high resolution with a 10 m grating spectrograph. The emission, which extends from 2670 to 1480 Å, consists entirely of bands of the B1Σ+–X1Σ+ (previously denoted as the V1Σ+–X1Σ+)system. From the analysis of 51 bands of the emission spectrum, constants of the vibrational levels of the X state from ν = 7 and 19 and of the B state from ν = 0 to 10 have been determined. The dissociation energy of HF has been found to be D0(HF) = 47 333 ± 60 cm−1. In the absorption spectrum, 56 bands of the B–X system have been identified. Vibrational levels of the B state between ν = 14 and 26 were found to be well behaved and readily analyzed, but levels between ν = 26 and 73 were found to be highly perturbed. Rydberg–Klein–Rees potential curves have been calculated for the B and X states and it is shown that at large internuclear distances the bonding of the B state is almost entirely ionic.

The Electronic Spectrum of HF+

1975 ◽  
Vol 53 (11) ◽  
pp. 1097-1108 ◽  
Author(s):  
S. Gewurtz ◽  
H. Lew ◽  
P. Flainek
Keyword(s):  
High Resolution ◽  
Emission Spectrum ◽  
Electronic Spectrum ◽  
Dissociation Energy ◽  
Theoretical Calculations ◽  
Detailed Comparison ◽  
X State ◽  
Vibrational Constants

The A2Σ+–X2Π emission spectrum of HF+, between 3580 and 4830 Å, has been photographed at high resolution and measurements on eight bands are reported. The analysis yields rotational and vibrational constants of the X state for ν = 0 to 2 and of the A state for ν = 0 to 3. A predissociation by rotation in the A2Σ+ state is observed and yields a dissociation energy of 3203 ± 50 cm−1 above the ν = 0, N = 0 level of this state. It is shown that this corresponds to a dissociation into H+(1S) + F(2P1/2). A detailed comparison with previous results obtained from photoelectron and photoionization experiments and from recent theoretical calculations is given.

THE ELECTRONIC EMISSION SPECTRUM AND MOLECULAR CONSTANTS OF IODINE MONOFLUORIDE

1966 ◽  
Vol 44 (2) ◽  
pp. 337-352 ◽  
Author(s):  
R. A. Durie
Keyword(s):  
High Resolution ◽  
Emission Spectrum ◽  
Dissociation Energy ◽  
Band System ◽  
Vibrational Analysis ◽  
Rotational Structure ◽  
Molecular Constants ◽  
Present Evidence ◽  
Halogen Compounds ◽  
Concave Grating

Observation by the author (Durie 1951) of a well-developed band system in the emission from an iodine–fluorine flame provided the first evidence for the existence of iodine monofluoride (IF), the last of the six possible diatomic inter-halogen compounds to be detected. The spectrum, which lies in the region 4 300 to 7 600 Å, has since been photographed under high resolution using a 21-ft concave grating spectrograph. The rotational structure of the bands is shown to be consistent with an A3Π0+ → X1Σ transition in the IF molecule. A rotational and vibrational analysis of the bands has been carried out and the molecular constants evaluated for IF. The results are as follows:[Formula: see text]The present evidence relating to the value of the dissociation energy of IF is discussed.

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.

scholarly journals Spectrum of the hydroxyl radical

1969 ◽  
Vol 47 (18) ◽  
pp. 1945-1957 ◽  
Author(s):  
C. Carlone ◽  
F. W. Dalby
Keyword(s):  
High Resolution ◽  
Hydroxyl Radical ◽  
Dissociation Energy ◽  
Spin Splitting ◽  
Oh Radical ◽  
Rotational Constants ◽  
Upper Limit ◽  
Vibrational Levels ◽  
State Formula ◽  
Potential Maximum

The B2Σ+ → A2Σ+ and C2Σ+ → A2Σ+ systems of OH and OD were photographed at high resolution. The apparent dissociation energy D0(A2Σ+) is calculated to be (18 847 ± 15) cm−1 for OH and (19 263 ± 15) cm−1 for OD. An upper limit to D0(X2Π3/2) of OH is deduced to be (35 420 ± 15) cm−1. Evidence for a potential maximum in the B2Σ+ state, which is about 100 cm−1 larger than that in the A2Σ+ state, is presented.The broadening of the rotational lines in several bands of both systems has established a strong predissociation of the A2Σ+ state near ν = 5 in OH. The lifetime of these predissociated levels is ≈10−11 s. A definite identification of the predissociating state has not been possible.Newly-discovered vibrational levels in the C2Σ+ state have led to the following constants, in cm−1, of the OH radical in the C2Σ+ state:[Formula: see text]Rotational constants and spin splitting constants in the A2Σ+ and B2Σ+ states, more accurate than previously available, are presented.

The 3300 Å band system of cyclobutanone

1969 ◽  
Vol 47 (11) ◽  
pp. 1235-1236 ◽  
Author(s):  
D. C. Moule
Keyword(s):  
High Resolution ◽  
Electronic State ◽  
Potential Function ◽  
Band System ◽  
Ultraviolet Spectrum ◽  
Vibrational Levels ◽  
Minimum Potential

The ultraviolet spectrum of cyclobutanone vapor has been recorded under conditions of high resolution. The oxygen wagging vibrational levels have been found to be strongly anharmonic in the 1A2 electronic state and have been fitted to a double minimum potential function.

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.

Electronic spectrum of H2O+

1976 ◽  
Vol 54 (20) ◽  
pp. 2028-2049 ◽  
Author(s):  
H. Lew
Keyword(s):  
Emission Spectrum ◽  
Electronic Spectrum ◽  
Ground State ◽  
Energy Levels ◽  
Bond Distance ◽  
Electronic States ◽  
Wavelength Region ◽  
Astrophysical Interest ◽  
Vibrational Levels ◽  
Wave Numbers

Many bands of the [Formula: see text] electronic emission spectrum of H2O+, occurring in the wavelength region 4000–7500 Å, have been analyzed. These include bands that have been observed in the tails of comets. The wavelengths and wave numbers of all assigned lines are tabulated. Accurate rotational constants for the first three bending vibrational levels of the ground state are given, as well as energy levels in the upper and lower electronic states. The O—H bond distance and the H—O—H angle in the [Formula: see text] (0, 0, 0) level are found to be 0.9988 Å and 110.46° respectively. Some predicted microwave and infrared lines that may be of astrophysical interest are included.

ABSORPTION SPECTRUM OF THE NO MOLECULE: IV. THE G2Σ−–X2Π SYSTEM

1964 ◽  
Vol 42 (5) ◽  
pp. 848-859 ◽  
Author(s):  
A. Lofthus ◽  
E. Miescher
Keyword(s):  
Absorption Spectrum ◽  
Dissociation Energy ◽  
Band System ◽  
The Other ◽  
High Dispersion ◽  
Electron Configuration ◽  
The Many ◽  
No Absorption ◽  
Overlapping Bands

High-dispersion plates of the NO absorption spectrum have been studied between 1600 and 1390 Å for the three isotopic molecules N14O16, N15O16, and N14O18, and G2Σ−–X2Π bands were sorted out from the many overlapping bands in the spectrum. The well-defined band system satisfies the established isotope relations. In contrast with most of the other known NO band systems G2Σ−–X2Π shows almost no perturbations. Vibrational and rotational analyses gave the following constants for the G2Σ− state of N14O16: Te = 62911.7 cm−1; ωe = 1085.54 cm−1, ωexe = 11.083 cm−1, ωeye = −0.1439 cm−1, Be = 1.2523 cm−1, αe = 0.0204 cm−1, γe = 1.3426 Å. The combination defect observed in the G2Σ−–X2Π bands agrees with the defect found in the A2Σ+–X2Π(γ) bands except in sign, which is opposite. Therefore, the symmetry of the G state is confirmed as 2Σ−. The "pure precession" relation between G2Σ− and X2Π is found to hold for the Λ-type doubling of X2Π. The diffuse structure of the band assigned to ν = 10 indicates that G2Σ− is predissociated by a repulsive 2Σ− state dissociating into 2D(N)+3P(O) atoms at 71660 cm−1. The dissociation energy and electron configuration for G2Σ− are discussed.

Spectrum of AsS. I. Analysis of the A′2Π3/2–X2Π3/2 Band System

1971 ◽  
Vol 49 (10) ◽  
pp. 1249-1254 ◽  
Author(s):  
Midori Shimauchi
Keyword(s):  
High Resolution ◽  
Emission Spectrum ◽  
Ground State ◽  
Band System ◽  
Vibrational Analysis ◽  
Quartz Tube ◽  
Rotational Analysis ◽  
Vibrational Constants

The emission spectrum of the AsS radical, excited in a quartz tube by a 2450 MHz oscillator, was photographed on a high resolution spectrograph from 2450 to 6900 Å. Seven bands around 6000 Å showing clear rotational structures were chosen for the first rotational analysis of the AsS spectrum. The bands were found to arise from a 2Π3/2–2Π3/2 transition. The rotational and vibrational constants of the two states derived from the present work are consistent with the previous vibrational analysis of the A′2Π3/2–X2Π3/2 system. The constants of the upper doublet component of the ground state, X2Π3/2, are ωe = 562.40 cm−1, ωexe = 2.02 cm−1, re = 2.0216 Å; the constants of the A′2Π3/2 state are ΔG′(1/2) = 403.37 cm−1, ν0,0 = 18 621.21 cm−1, re = 2.2500 Å.

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.

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