THE SPECTRUM AND STRUCTURE OF THE HNO MOLECULE

1958 ◽  
Vol 36 (10) ◽  
pp. 1336-1371 ◽  
Author(s):  
F. W. Dalby
Keyword(s):  
Nitric Oxide ◽  
Absorption Spectrum ◽  
Electronic State ◽  
Flash Photolysis ◽  
Molecular Geometry ◽  
Rotational Analysis ◽  
Experimental Conditions ◽  
Long Wavelength ◽  
Lower Electronic State ◽  
State Formula

The absorption spectrum of HNO in the region 6500–7700 Å has been photographed on a 35-ft grating. The observed spectrum consists of three bands: an intense one at the long-wavelength end of the spectrum and two weaker bands towards shorter wavelengths. All the bands have extensive rotational structure of the perpendicular type. The spectrum was observed after the flash photolysis of nitromethane, nitroethane, isoamyl nitrite, and mixtures of nitric oxide and ammonia. The "lifetime" of the HNO was about 1/10 second under our experimental conditions. The spectrum of DNO has also been photographed. From the constants obtained from the rotational analysis the molecular geometry has been determined. For the lower electronic state[Formula: see text]For the upper electronic state[Formula: see text]The most probable identification of the observed electronic transition is 1A″ ← 1A′.

Absorption Spectrum of HSiI

1972 ◽  
Vol 50 (6) ◽  
pp. 531-543 ◽  
Author(s):  
J. Billingsley
Keyword(s):  
Absorption Spectrum ◽  
Electronic State ◽  
Isotope Shift ◽  
Flash Photolysis ◽  
Bond Angle ◽  
Rotational Analysis ◽  
Lower Electronic State ◽  
Deuterium Isotope Shift ◽  
Axis Switching

A new absorption spectrum in the region 4600–5600 Å has been discovered in the flash photolysis of silyl iodide, SiH3I. A rotational analysis, together with the observation of a deuterium isotope shift, has shown that the spectrum is due to the HSiI radical.The lower electronic state of HSiI is a 1A′ state with a bond angle of ~103°, and the upper state is 1A″ with angle ~116°. Axis-switching effects, due to the increase in bond angle, cause the appearance of ΔK = 0, ± 2 subbands, in addition to the ordinary ΔK = ± 1 subbands.

The A2Πi–X2Πi absorption spectrum of BrO

1981 ◽  
Vol 59 (12) ◽  
pp. 1908-1916 ◽  
Author(s):  
M. Barnett ◽  
E. A. Cohen ◽  
D. A. Ramsay
Keyword(s):  
Absorption Spectrum ◽  
Absorption Spectra ◽  
Ground State ◽  
Flash Photolysis ◽  
Absorption Bands ◽  
Long Wavelength ◽  
Numbering Scheme ◽  
Ozonized Oxygen ◽  
Good Agreement

Absorption spectra of isotopically enriched 81Br16O and of normal BrO have been obtained by the flash photolysis of mixtures of bromine and ozonized oxygen. Rotational analyses are given for the 7–0, 12–0, 18–0, 19–0, 20–0, 21–0, 7–1, and 20–1 A2Π3/2–X2Π3/2 sub-bands of 81Br16O. The value for [Formula: see text] is found to be 722.1 ± 1.1 cm−1 in good agreement with the value calculated from microwave constants. Several additional bands have been found at the long wavelength end of the spectrum, necessitating a revision of the vibrational numbering scheme for both the emission and absorption bands. "Hot" bands up to ν″ = 6 have been observed in the absorption spectrum for the 2Π3/2 component of the ground state but no bands have yet been identified from the 2Π1/2 component.

The ultraviolet absorption spectrum of the F 2 CN radical

1967 ◽  
Vol 300 (1462) ◽  
pp. 405-414 ◽  
Keyword(s):  
Molecular Structure ◽  
Absorption Spectrum ◽  
Ground State ◽  
Flash Photolysis ◽  
Ultraviolet Absorption ◽  
Ultraviolet Absorption Spectrum ◽  
Rotational Analysis ◽  
Absorption Bands ◽  
New System

A new system of absorption bands near 3600 Å has been observed during the flash photolysis of CF 3 NCF 2 and is ascribed to the free F 2 CN radical. The rotational analysis of the 0–0 band leads to the ground state molecular structure r CF = 1.310 Å (assumed), r CN = 1.265 ± 0.02 Å, FCF angle = 113.5 + 1°. The bands are shown to be type A bands arising from the transition 2 A 1 ← 2 B 2 , and the spectrum is compared with those of the iso-electronic molecules NO 3 and F 2 BO.

scholarly journals Time-Resolved Study of Light-Induced Ground State Proton Transfer from Acid Medium to 4-Nitrophenolate

2020 ◽  
Author(s):  
Leandro Scorsin ◽  
Leticia Martins ◽  
Haidi Fiedler ◽  
Faruk Nome ◽  
RENE NOME
Keyword(s):  
Acetic Acid ◽  
Proton Transfer ◽  
Electronic State ◽  
Ground State ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Proton Transfer Reaction ◽  
Ground Electronic State ◽  
Experimental Conditions

In the present work, we study the transient laser-induced formation of 4-nitrophenolate (4-NPO<sup>-</sup>) in the ground electronic state and subsequent proton transfer reaction with acetic acid and water with numerical calculations and laser flash photolysis. We employ the Debye-Smoluchowski spherically-symmetric diffusion model of photoacid proton transfer to determine experimental conditions for studying thermally activated chemical reactions in the ground electronic state. Numerically calculated protonation and deprotonation probabilities for 4-NPO<sup>-</sup> and 4-nitrophenol (4-NPOH) in both ground and excited states showed the feasibility of efficiently producing the ground state anion in the photoacid cycle. We performed laser flash photolysis measurements of 4-NPOH to characterize the photo-initiated ground state protonation and deprotonation rate constants of 4-NPO<sup>-</sup>/4-NPOH as a function of acetic acid, pH, temperature and viscosity. Overall, the work presented here shows a simple way to study fast competing bimolecular proton transfer reactions in non-equilibrium conditions in the ground electronic state <i>(GSPT)</i>.

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.

scholarly journals Time-Resolved Study of Light-Induced Ground State Proton Transfer from Acid Medium to 4-Nitrophenolate

2020 ◽  
Author(s):  
Leandro Scorsin ◽  
Leticia Martins ◽  
Haidi Fiedler ◽  
Faruk Nome ◽  
RENE NOME
Keyword(s):  
Acetic Acid ◽  
Proton Transfer ◽  
Electronic State ◽  
Ground State ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Proton Transfer Reaction ◽  
Ground Electronic State ◽  
Experimental Conditions

In the present work, we study the transient laser-induced formation of 4-nitrophenolate (4-NPO<sup>-</sup>) in the ground electronic state and subsequent proton transfer reaction with acetic acid and water with numerical calculations and laser flash photolysis. We employ the Debye-Smoluchowski spherically-symmetric diffusion model of photoacid proton transfer to determine experimental conditions for studying thermally activated chemical reactions in the ground electronic state. Numerically calculated protonation and deprotonation probabilities for 4-NPO<sup>-</sup> and 4-nitrophenol (4-NPOH) in both ground and excited states showed the feasibility of efficiently producing the ground state anion in the photoacid cycle. We performed laser flash photolysis measurements of 4-NPOH to characterize the photo-initiated ground state protonation and deprotonation rate constants of 4-NPO<sup>-</sup>/4-NPOH as a function of acetic acid, pH, temperature and viscosity. Overall, the work presented here shows a simple way to study fast competing bimolecular proton transfer reactions in non-equilibrium conditions in the ground electronic state <i>(GSPT)</i>.

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.

Rotational Structure at the Long Wavelength End of the 2900 Å System of SO2

1974 ◽  
Vol 52 (15) ◽  
pp. 1443-1457 ◽  
Author(s):  
Y. Hamada ◽  
A. J. Merer
Keyword(s):  
Electronic State ◽  
Geometric Structure ◽  
Theoretical Calculations ◽  
Rotational Structure ◽  
Rotational Analysis ◽  
Long Wavelength ◽  
Isotope Data ◽  
Type C

Rotational analyses have been carried out for the three longest wavelength bands observable in the '2900 Å system' of SO2 (at 3340, 3359, and 3395 Å). Although the bands are perturbed quite severely it has been possible to prove that they are type C bands, and that the approximate upper state geometric structure of the molecule is r(S—O) = 1.53 Å, [Formula: see text]. Comparison with the theoretical calculations of Hillier and Saunders now leaves little doubt that the upper electronic state is the π → π* 1A2 state, appearing in absorption by Herzberg–Teller mixing through Q3′(b2), as recently proposed by Dixon and Hallé. A vibrational numbering for these bands is given, which is consistent with the inertial defect obtained from the rotational analysis, and with recent isotope data published by Brand and Nanes: the 3395 Å band appears to be 031–000, and the electronic origin falls near 27 930 cm−1.

The Absorption Spectrum of Isotopic Diatomic Antimony ( 123Sb-123Sb). Analysis of the D ← X System in the 2860—2920 Å Region

1976 ◽  
Vol 31 (2) ◽  
pp. 145-157 ◽  
Author(s):  
Abdel Mooti Sibai ◽  
Ari Topouzkhanian ◽  
Pierre Perdigon
Keyword(s):  
Absorption Spectrum ◽  
Electronic State ◽  
Rotational Constant ◽  
Rotational Analysis ◽  
Vibrational Levels ◽  
X State

Abstract A rotational analysis of several bands of the D←X system of 123Sb−123Sb is carried out. It is shown that the hitherto assumed vibrational classification of the D←X system is certainly incorrect, as well as a previously given value for the rotational constant of the X state. B(X1∑g+, ν=0) is found equal to 0.044263 cm-1. The perturbations appearing in the various vibrational levels are interpreted in terms of interactions with a new electronic state, labelled L.

The absorption spectrum of the free SiH2 radical

1968 ◽  
Vol 46 (22) ◽  
pp. 2485-2490 ◽  
Author(s):  
I. Dubois
Keyword(s):  
Absorption Spectrum ◽  
Electronic State ◽  
Vibrational Level ◽  
Visible Region ◽  
Rotational Structure ◽  
Lower State ◽  
High Dispersion ◽  
Bending Vibration ◽  
Lower Electronic State

The absorption spectrum of SiH2 in the visible region has been photographed at high dispersion and the rotational structure of three bands has been analyzed. In the lower electronic state 1A1 the HSiH angle is 92° 5′ and the Si–H distance 1.516 Å, while in the upper state these parameters are 123° and 1.487 Å, respectively. The observed bands correspond to excitation of the bending vibration [Formula: see text] in the upper state. In the lower state, only one excited vibrational level, 010, has been observed, yielding [Formula: see text].

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