Rotational Analysis of Bands of the Transition of PH2

1972 ◽  
Vol 50 (19) ◽  
pp. 2265-2276 ◽  
Author(s):  
J. M. Berthou ◽  
B. Pascat ◽  
H. Guenebaut ◽  
D. A. Ramsay
Keyword(s):  
Excited State ◽  
Ground State ◽  
Electronic Transition ◽  
Rotational Analysis ◽  
Empirical Formulas ◽  
Molecular Constants ◽  
Vibrational Levels

Rotational analyses have been carried out for the 0ν′20–000 bands of the [Formula: see text] electronic transition of PH2 with ν′2 = 1–8. Approximately 1000 lines have been assigned. The earlier analysis of the 000–000 band has been extended and improved molecular constants obtained. The Hamiltonian used for this band does not fit the excited state levels with [Formula: see text]. Term values are therefore given for all observed levels. Empirical formulas are presented which give approximate fits to the higher levels. Numerous rotational perturbations are found in the excited state. Perturbations up to 0.6 cm−1 are also found in the 000 level of the excited state. These latter perturbations can only be caused by the higher vibrational levels of the ground state.

The absorption spectrum of NH2 between 6250 and 9500 Å

1976 ◽  
Vol 54 (17) ◽  
pp. 1804-1814 ◽  
Author(s):  
J. W. C. Johns ◽  
D. A. Ramsay ◽  
S. C. Ross
Keyword(s):  
Absorption Spectrum ◽  
Excited State ◽  
Ground State ◽  
Absorption System ◽  
Molecular Constants ◽  
Bending Vibration ◽  
Long Wavelength ◽  
Vibrational Levels

The earlier analysis by Dressier and Ramsay of the [Formula: see text] absorption system of NH2 has been considerably extended at the long wavelength end of the spectrum. All the low-lying vibronic levels of the excited state have been identified up to ν2′ = 8. These levels are 010(K = 0), 020(K = 1), 030(K = 0,2), 040(K = 1,3), 050(K = 0,2,4), 060(K = 1,3,5), 070(K = 0,2,4,6), and 080(K = 1,3,5,7). Large perturbations (~ 200 cm−1) have been observed between some of these levels and high vibrational levels of the ground state. Accurate molecular constants have been obtained for the ground state and for the first level involving the bending vibration (ν2″ = 1).

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.

The spectrum and structure of the free BH 2 radical

1967 ◽  
Vol 298 (1453) ◽  
pp. 142-159 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Excited State ◽  
Ground State ◽  
Electronic Transition ◽  
Flash Photolysis ◽  
Molecular Constants ◽  
Isotope Shifts ◽  
Geometrical Data

A new absorption spectrum has been found in the flash photolysis of H 3 BCO which, from its structure and the observed isotope shifts can be unambiguously assigned to the free BH 2 radical. The spectrum represents a transition similar to those previously observed in NH 2 and CH 2 . The molecule is linear in the excited state but bent (with an angle of 131°) in the ground state. Molecular constants and geometrical data are evaluated. The electronic transition is 2 B 1 ( II u ) – 2 A 1 and fits well with expectation from the Walsh diagram for X H 2 molecules.

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]

Rotational Analysis of the lΠ–XlΣ+ System of C80Se

1974 ◽  
Vol 52 (9) ◽  
pp. 813-820 ◽  
Author(s):  
René Stringat ◽  
Jean-Paul Bacci ◽  
Marie-Hélène Pischedda
Keyword(s):  
Emission Spectrum ◽  
Ground State ◽  
High Frequency ◽  
Rotational Analysis ◽  
Molecular Constants ◽  
High Frequency Discharge ◽  
Perturbed State ◽  
Simple Evaluation ◽  
Π State

The strongly perturbed 1Π–X1Σ+ system of C80Se has been observed in the emission spectrum of a high frequency discharge through selenium and carbon traces in a neon atmosphere. The analysis of five bands yields, for the molecular constants of the ground state, the values Be″ = 0.5750 cm−1, [Formula: see text], αe″ = 0.00379 cm−1, re″ = 1.676 Å, ΔG″(1/2) = 1025.64 cm−1, and ΔG″(3/2) = 1015.92 cm−1. The numerous perturbations in the 1Π state prohibit the simple evaluation of the constants of the perturbed state and of the perturbing ones.

Absorption spectrum of SiH in the vacuum ultraviolet

1969 ◽  
Vol 47 (18) ◽  
pp. 1889-1897 ◽  
Author(s):  
G. Herzberg ◽  
A. Lagerqvist ◽  
B. J. McKenzie
Keyword(s):  
Absorption Spectrum ◽  
Electronic Transition ◽  
Vacuum Ultraviolet ◽  
Rotational Analysis ◽  
Molecular Constants

A new electronic transition of SiH has been observed in absorption near 1907 Å in flash discharges through mixtures of SiH4 and H2. The rotational analysis shows this transition to be of the type 2Σ+−2Π. The corresponding transition of SiD has also been observed and analyzed. The D2Δ−X2Π transition near 2058 Å which was observed and analyzed by Verma in SiD has been measured here for SiH, where the lines are much broader on account of predissociation. The predissociation phenomena in SiH and SiD and the electron configurations are briefly discussed, and the presently known molecular constants of these molecules are summarized.

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.

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 ABSORPTION SPECTRUM OF BO2

1961 ◽  
Vol 39 (12) ◽  
pp. 1738-1768 ◽  
Author(s):  
J. W. C. Johns
Keyword(s):  
Absorption Spectrum ◽  
Excited State ◽  
Detailed Analysis ◽  
Ground State ◽  
Flash Photolysis ◽  
Electronic Transitions ◽  
Molecular Constants ◽  
Boron Trichloride ◽  
Symmetric Molecule ◽  
First Excited State

The boron flame bands have been observed in absorption during the flash photolysis of mixtures of boron trichloride and oxygen. Detailed analysis of the spectrum has shown that the bands arise from two electronic transitions in the linear symmetric molecule BO2, [Formula: see text] and A2Πu−X2Πg. The main molecular constants, in cm−1 except for r0, are summarized below:[Formula: see text]Both 2Π states show the Renner effect. In the ground state the Renner parameter, εω2, was found to be −92.2, whereas in the first excited state it is much smaller, −13.1 cm−1.

Unimolecular Electrical Rectification Down to 105 K, and Spectroscopy of Hexadecylquinolinium Tricyanoquinodimethanide

1999 ◽  
Vol 582 ◽  
Author(s):  
R. M. Metzger
Keyword(s):  
Electrical Conductivity ◽  
Excited State ◽  
Single Molecule ◽  
Ground State ◽  
Electronic Transition ◽  
Electrical Current ◽  
Langmuir Blodgett ◽  
Dc Electrical Conductivity ◽  
Forward Current ◽  
First Excited State

ABSTRACTA Langmuir-Blodgett monolayer of γ-(n-hexadecyl)quinolinum tricyanoquinodimethanide, C16H33Q-3CNQ (1), sandwiched between Al electrodes, shows asymmetric DC electrical conductivity between 370 K and 105 K. The enhanced forward current is attributable to rectification of electrical current by a single molecule, and is explained by an electronic transition from a high-moment zwitterionic ground state to a low-moment undissociated first excited state.

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