Spectrum of the CN molecule. I. Absorption in the vacuum ultraviolet

1970 ◽  
Vol 48 (10) ◽  
pp. 1192-1199 ◽  
Author(s):  
Barry L. Lutz
Keyword(s):  
Vacuum Ultraviolet ◽  
Band System ◽  
Vibrational Analysis ◽  
Electronic States ◽  
Ultraviolet Absorption Spectrum ◽  
Molecular Constants ◽  
Weak Band ◽  
Vibrational Levels ◽  
First Time ◽  
Π State

The vacuum ultraviolet absorption spectrum of CN is observed for the first time revealing a weak band system between 1490 and 1820 Å. Rotational and vibrational analysis shows the upper state to be the known E2Σ+ state. Four new vibrational levels are reported, resulting in the following molecular constants for the E state (cm−1):[Formula: see text]The strength of the absorption and its significance in astrophysics is discussed. The dissociation limits and the electron configurations of all known electronic states of CN are also discussed, and a tentative assignment of a previously unassigned 2Π state is proposed.

BAND SPECTRUM AND STRUCTURE OF THE CH+ MOLECULE; IDENTIFICATION OF THREE INTERSTELLAR LINES

1942 ◽  
Vol 20a (6) ◽  
pp. 71-82 ◽  
Author(s):  
A. E. Douglas ◽  
G. Herzberg
Keyword(s):  
Ground State ◽  
Band System ◽  
Lower State ◽  
Band Spectrum ◽  
Interstellar Space ◽  
Molecular Constants ◽  
Vibrational Levels ◽  
State Formula ◽  
Heat Of Dissociation ◽  
Π State

In a discharge through helium, to which a small trace of benzene vapour is added, a new band system of the type 1Π – 1Σ is found which is shown to be due to the CH+ molecule. The R(0) lines of the 0–0, 1–0, and 2–0 bands of the new system agree exactly with the hitherto unidentified interstellar lines 4232.58, 3957.72, 3745.33 Å, thus proving that CH+ is present in interstellar space. At the same time this observation of the band system in absorption shows that the lower state 1Σ is the ground state of the CH+ molecule. The new bands are closely analogous to the 1II – 1Σ+ BH bands. The analysis of the bands leads to the following vibrational and rotational constants of CH+ in its ground state: [Formula: see text], Be″ = 14.1767, αe″ = 0.4898 cm.−1. The internuclear distance is re″ = 1.1310∙10−8 cm. (for further molecular constants see Table V). From the vibrational levels of the upper 1Π state the heat of dissociation of CH+ can be obtained within fairly narrow limits: D0(CH+) = 3.61 ± 0.22 e.v. From this value the ionization potential of CH is derived to be I(CH) = 11.13 ± 0.22 e.v. The bearing of this value on recent work on ionization and dissociation of polyatomic molecules by electron impacts is briefly discussed.

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.

ULTRAVIOLET SPECTRA OF LiH AND LiD

1957 ◽  
Vol 35 (10) ◽  
pp. 1204-1214 ◽  
Author(s):  
R. Velasco
Keyword(s):  
Excited State ◽  
Ground State ◽  
Band System ◽  
Electronic States ◽  
High Dispersion ◽  
Dissociation Energies ◽  
Near Ultraviolet ◽  
Path Lengths ◽  
Vibrational Constants ◽  
Π State

The absorption spectra of LiH and LiD have been observed in the near ultraviolet with high dispersion and absorbing path lengths up to 16 meters. A new band system has been found in each molecule involving the ground state and a 1Π excited state. Rotational and vibrational analyses of this system have been carried out and rotational and vibrational constants for the upper state have been determined. The observed breaking off of the rotational structure of the bands of this B1Π—X1Σ+ system has been interpreted as due to predissociation by rotation. With this assumption very accurate dissociation limits of the B1Π state have been obtained. From these dissociation limits the dissociation energies of the three known electronic states of LiH and LiD have been calculated. In particular the dissociation energies (D0) of the ground states of LiH and LiD have been found to be 2.4288 ± 0.0002 ev. and 2.4509 ± 0.0010 ev., respectively.

Emission spectra of group IV monohalide ions: , 3Π1–X1Σ+ emissions of SiBr+

1984 ◽  
Vol 62 (4) ◽  
pp. 353-360 ◽  
Author(s):  
M. Tsuji ◽  
K. Shinohara ◽  
S. Nishitani ◽  
T. Mizuguchi ◽  
Y. Nishimura
Keyword(s):  
Thermal Energy ◽  
Vibrational Temperature ◽  
Vibrational Analysis ◽  
Emission Spectra ◽  
Ionic Species ◽  
Group Iv ◽  
Rare Gas ◽  
Molecular Constants ◽  
Vibrational Levels ◽  
Effective Vibrational Temperature

Emission spectra of SiBr4 in the rare gas flowing afterglows have been measured to detect and identify SiBr+ emissions. Two systems of SiBr+ emissions were detected in the He, Ne, and Ar afterglows in the region from 335 to 380 nm. By analogy with the emission spectrum of SiCl+, they were ascribed to the [Formula: see text]–X1Σ+ and a3Π1–X1Σ+ subsystems of SiBr+. The vibrational analysis of the latter system gave the following molecular constants for the a3Π1 state: T0 = 29 140 ± 5 cm−1 and ΔG(1/2) = 392.0 ± 3.7 cm−1. The SiBr+ emissions disappeared when ionic species were removed from the afterglows, indicating that the emitting SiBr+ states were produced through thermal-energy reactions of rare gas ions with SiBr4. In the He and Ne afterglows, the [Formula: see text] ions were produced in higher vibrational levels than in the Ar afterglow. The relative vibrational populations in the He and Ne afterglows were nearly exponential with an effective vibrational temperature of 460 ± 30 K.

Analyse vibrationnelle et rotationnelle de la transition A2Σ+–X2Πi de la molécule 63Cu80Se

1976 ◽  
Vol 54 (16) ◽  
pp. 1664-1668 ◽  
Author(s):  
Y. Lefebvre ◽  
J. L. Bocquet
Keyword(s):  
Band System ◽  
High Dispersion ◽  
Rotational Analysis ◽  
Molecular Constants ◽  
Visible Band ◽  
Π State

High dispersion vibrational and rotational analysis of a 63Cu80Se visible band system has been performed.The presence of a splitting proportional to [Formula: see text] in each observed subsystem indicates that these bands arise from a transition from a 2Σ state (with γ-type doubling) to a 2Π state. This hypothesis allows us to derive specific molecular constants of these two states.

Zeeman effects in the band System of sulfur dioxide

1976 ◽  
Vol 54 (2) ◽  
pp. 186-196 ◽  
Author(s):  
J. C. D. Brand ◽  
J. L. Hardwick ◽  
D. R. Humphrey ◽  
Y. Hamada ◽  
A. J. Merer
Keyword(s):  
Sulfur Dioxide ◽  
Ground State ◽  
Band System ◽  
Zeeman Effect ◽  
Electronic States ◽  
Vibrational Levels ◽  
Asymmetric Rotor ◽  
Most Probable Explanation ◽  
Rotational Coupling ◽  
Singlet Transition

Bands of the [Formula: see text] system of sulfur dioxide appear as structured absorption superimposed on an apparent continuum. A portion of this System between 3250 and 3000 Å has been recorded in a magnetic field and is found to exhibit a strong Zeeman effect, contrary to expectation for a singlet-singlet transition between bent states of an asymmetric rotor. Line shift and broadening is observed in relatively low fields (< 3 kG), and the spectra become diffuse in fields of ~ 10 kG. The possibility is considered that the magnetic moment in the à state results from rotational coupling of singlet electronic states but it appears unlikely that the angular momentum so developed is sufficient to account for the observations. The most probable explanation of the magnetic sensitivity is that the à state couples with a background of interacting vibrational levels of the ground state and low lying states of the triplet manifold.

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.

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.

First Observation of the BeXe+ Molecule: The A2Π–X2Σ Band System in Emission

1975 ◽  
Vol 53 (20) ◽  
pp. 2321-2325 ◽  
Author(s):  
J. A. Coxon ◽  
W. E. Jones ◽  
K. V. Subbaram
Keyword(s):  
Ground State ◽  
Microwave Discharge ◽  
Band System ◽  
Vibrational Analysis ◽  
Dipole Interaction ◽  
Binding Energies ◽  
Molecular Constants ◽  
Induced Dipole ◽  
Beryllium Chloride

Twenty-three new violet degraded bands in the region λ 4100–4700 Å have been observed in emission from a microwave discharge through beryllium chloride and flowing xenon at total pressures near 200 Torr. The band system is attributed to the A2Π–X2Σ+ transition of the new molecule BeXe+. Approximate molecular constants are reported from the vibrational analysis. The observation and assignment of this spectrum of BeXe+ confirm our recent results on the BeAr+ and BeKr+ molecules, for which it was proposed that the ion-induced dipole interaction was largely responsible for the ground state binding energies.

The electronic spectrum of the CS+ molecular ion: rotational analysis and perturbation effects in the A2Πi–X2Σ+ transition

1978 ◽  
Vol 56 (5) ◽  
pp. 587-600 ◽  
Author(s):  
D. Gauyacq ◽  
M. Horani
Keyword(s):  
Carbon Disulfide ◽  
Ground State ◽  
Valence Electron ◽  
Band System ◽  
Local Perturbation ◽  
Rotational Analysis ◽  
Molecular Constants ◽  
Molecular Ion ◽  
Vibrational Levels ◽  
The Difference

A new emission spectrum in the red region (6000–8000 Å) has been recorded from a low pressure hot cathode discharge through carbon disulfide. This band system has been assigned to the A2Πi–X2Σ+ transition of the CS+ molecular ion on the basis of the rotational analysis and comparison with other nine valence-electron molecules. Molecular constants have been obtained by direct least squares fits of the line frequencies to the difference of the eigenvalues of standard 2Π and 2Σ+ matrices.A local perturbation in the A2Πi (ν = 5) state has been studied quantitatively. The position of the perturbing vibrational level in the X2Σ+ state has been determined within a few centimetre−1. This study gave a consistent set of molecular constants for the ground state of CS+ and allowed a partial deperturbation treatment of the observed vibrational levels of the excited A2Πi state.Numerous bands are also observed in the 4000 Å region. A discussion is given concerning the possible assignment of bands at 4059 and 4110 Å to the CS+B2Σ+–A2Πi (0,0) transition.

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