The Dielectric Discharge as an Efficient Generator of Active Nitrogen for Chemiluminescence and Analysis

A predominantly blue “active nitrogen” afterglow was generated in pure flowing nitrogen or in air by using a dielectric discharge at pressures from 1 to 20 Torr. The afterglow contains triplet state molecules and vibrationally excited ground state molecules. These species are produced directly by electron impact without the formation and recombination of nitrogen atoms. The most intense emission is the N2 second positive band system. The N2 first positive and N2+ first negative systems are also observed. The spectral and electrical properties of this discharge are discussed in order to establish guidelines for the analytical use of the afterglow for chemiluminescence reactions. The metastatic nitrogen efficiently transfers its energy to atomic and molecular species which are introduced into the gas phase and these excited species emit characteristic radiation. The effects of electrothermal atomization of Zn and the introduction of gaseous species (e.g., NO) on the afterglow are described.

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Energy transfer rates for vibrationally excited gas-phase azulene in the electronic ground state

Chemical Physics Letters ◽

10.1016/0009-2614(81)80010-3 ◽

1981 ◽

Vol 78 (2) ◽

pp. 253-258 ◽

Cited By ~ 45

Author(s):

Gregory P. Smith ◽

John R. Barker

Keyword(s):

Energy Transfer ◽

Gas Phase ◽

Ground State ◽

Electronic Ground State ◽

Vibrationally Excited ◽

Transfer Rates ◽

Electronic Ground

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Etude à basse température dans l'infrarouge proche du dimère (NO)2

Canadian Journal of Physics ◽

10.1139/p84-048 ◽

1984 ◽

Vol 62 (4) ◽

pp. 322-329 ◽

Cited By ~ 36

Author(s):

V. Menoux ◽

R. Le Doucen ◽

C. Haeusler ◽

J. C. Deroche

Keyword(s):

Excited State ◽

Gas Phase ◽

Ground State ◽

Near Infrared ◽

Heat Of Formation ◽

Wave Number ◽

Vibrational Modes ◽

Vibrationally Excited ◽

Rotational Constants ◽

Absorption Intensity

The spectrum of the dimer (NO)2 in the gas phase has been studied in the near infrared at temperatures between 118 and 138 K. More specifically, the measure of absorption intensity of the ν4 and ν1 + ν4 bands has yielded the heat of formation of the dimer, −2.25 kcal/mol at 128 K, and revealed the influence of the low vibrational modes on this measure. The observation of the ν4 – ν6, difference band has yielded the wave number value of the ν6, fundamental band, forbidden in the infrared. The rotational constants of the vibrationally excited state were found to be larger than the ground state rotational constants, this result being very unusual.

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Photochemical studies of unimolecular processes III. Subsidiary processes in the photolysis of cycloheptatriene

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1970.0071 ◽

1970 ◽

Vol 316 (1524) ◽

pp. 143-151 ◽

Cited By ~ 8

Keyword(s):

Gas Phase ◽

Ground State ◽

Hydrogen Atoms ◽

Vibrationally Excited ◽

Sufficient Energy ◽

Benzyl Radicals

In addition to toluene, the photolysis of cyclo[l. 3. 5]heptatriene (CHT) in the gas phase yields small amounts of benzene, methane, ethane, cyclopentadiene and acetylene. Most of the toluene molecules formed by the photo-isomerization of CHT have sufficient energy to dissociate to benzyl radicals and hydrogen atoms; the small fraction which do are responsible for the first three minor products. Cyclopentadiene and acetylene arise from vibrationally excited ground state CHT molecules with energies greater than 268 ± 12 kJ/mol, bicyclo[2. 2. l]heptadiene being the intermediate involved.

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Vibrationally Excited Ground‐State Nitrogen in Active Nitrogen

The Journal of Chemical Physics ◽

10.1063/1.1744171 ◽

1958 ◽

Vol 28 (3) ◽

pp. 510-511 ◽

Cited By ~ 81

Author(s):

Frederick Kaufman ◽

John R. Kelso

Keyword(s):

Ground State ◽

Vibrationally Excited ◽

Active Nitrogen

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CN Emission in Active Nitrogen. II. The Role of Energy Transfer and Atom Transfer Reactions in CN(X2Σ+) Excitation

Canadian Journal of Chemistry ◽

10.1139/v72-407 ◽

1972 ◽

Vol 50 (16) ◽

pp. 2527-2536 ◽

Cited By ~ 16

Author(s):

G. M. Provencher ◽

D. J. McKenney

Keyword(s):

Energy Transfer ◽

Ground State ◽

Absolute Intensity ◽

Vibrationally Excited ◽

Active Nitrogen ◽

Band Emission ◽

Electronically Excited ◽

Order Of Magnitude ◽

Three Body ◽

A Minor

A simplified mechanism is presented for excitation of ground state CN(X2Σ+) formed from carbonaceous impurity in flowing N2 subjected to a microwave discharge. Analysis of absolute intensity data from spectrometer recordings of CN(B2Σ+ → X2Σ+) violet band emission enabled order of magnitude estimates of rate constants for CN(X2Σ+) excitation by energy transfer from vibrationally excited ground state nitrogen, [Formula: see text][Formula: see text]and formation of electronically excited NCN* in a three body reaction[Formula: see text]Energy transfer from [Formula: see text] is shown to be a minor source of excitation of CN to radiative levels. N2(A) is a source of vibrationally excited ground state nitrogen, [Formula: see text] which in turn excites CN. Vibrational population profiles under all conditions in this work are shown to be primarily a function of [Formula: see text] Evidence for the participation of the A2Π state of CN is shown in the population maxima at ν = 4 and 10 of the B2Σ+ state.

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Microwave Spectrum of 1-Butene Oxide

Zeitschrift für Naturforschung A ◽

10.1515/zna-1978-1109 ◽

1978 ◽

Vol 33 (11) ◽

pp. 1312-1322

Author(s):

S. O. Ljunggren ◽

P. J. Mjöberg ◽

J . E. Bäckvall

Keyword(s):

Dipole Moment ◽

Gas Phase ◽

Internal Rotation ◽

Barrier Height ◽

Excited States ◽

Ground State ◽

Microwave Spectrum ◽

Frequency Region ◽

Centrifugal Distortion ◽

Vibrationally Excited

The microwave spectrum of 1-butene oxide in the gas phase has been studied in the frequency region 18.0-39.0 GHz. The spectrum observed arose from a rotamer with a dihedral H-C2-C3-C4 angle of 59° ± 1°. In addition to several Q-branch progressions the spectrum contained several long perpendicular RP and PR progressions. However, of the ground state lines, only the intermediate PR transitions showed internal rotation splittings that could be resolved to yield a barrier height of 3.02 kcal mol-1. The value derived from the line splittings of the first excited methyl torsional state was slightly higher (3.17 kcal mol-1) but must be regarded as being less reliable. The components of the dipole moment, the rotational constants, and the quartic and sextic centrifugal distortion coefficients for the ground state and three vibrationally excited states were determined.

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Excited-State Dynamics in the RNA Nucleotide Uridine 5’-Monophosphate Investigated by Femtosecond Broadband Transient Absorption Spectroscopy

10.26434/chemrxiv.7860023 ◽

2019 ◽

Author(s):

Matthew M. Brister ◽

Carlos Crespo-Hernández

Keyword(s):

Excited State ◽

Excited States ◽

Ground State ◽

Transient Absorption ◽

Electronic Energy ◽

Transient Absorption Spectroscopy ◽

Electronic Relaxation ◽

Vibrationally Excited ◽

Excited State Dynamics ◽

Π State

Damage to RNA from ultraviolet radiation induce chemical modifications to the nucleobases. Unraveling the excited states involved in these reactions is essential, but investigations aimed at understanding the electronic-energy relaxation pathways of the RNA nucleotide uridine 5’-monophosphate (UMP) have not received enough attention. In this Letter, the excited-state dynamics of UMP is investigated in aqueous solution. Excitation at 267 nm results in a trifurcation event that leads to the simultaneous population of the vibrationally-excited ground state, a longlived 1nOπ* state, and a receiver triplet state within 200 fs. The receiver state internally convert to the long-lived 3ππ* state in an ultrafast time scale. The results elucidate the electronic relaxation pathways and clarify earlier transient absorption experiments performed for uracil derivatives in solution. This mechanistic information is important because long-lived nπ* and ππ* excited states of both singlet and triplet multiplicities are thought to lead to the formation of harmful photoproducts.

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ROTATIONAL ANALYSIS OF THE β BANDS OF PHOSPHORUS MONOXIDE

Canadian Journal of Physics ◽

10.1139/p59-019 ◽

1959 ◽

Vol 37 (2) ◽

pp. 136-143 ◽

Cited By ~ 26

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.

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The Microwave Spectrum of 3,4-Dihydro-1,2-Pyran

Zeitschrift für Naturforschung A ◽

10.1515/zna-1985-0909 ◽

1985 ◽

Vol 40 (9) ◽

pp. 913-919

Author(s):

Juan Carlos López ◽

José L. Alonso

Keyword(s):

Dipole Moment ◽

Excited States ◽

Ground State ◽

Principal Axis ◽

Microwave Spectrum ◽

Average Intensity ◽

Ring Conformation ◽

Vibrationally Excited ◽

Rotational Constants ◽

Displacement Measurements

Abstract The rotational transitions of 3,4-dihydro-1,2-pyran in the ground state and six vibrationally excited states have been assigned. The rotational constants for the ground state (A = 5198.1847(24), B = 4747.8716(24) and C = 2710.9161(24) have been derived by fitting μa, μb and μc-type transitions. The dipole moment was determined from Stark displacement measurements to be 1.400(8) D with its principal axis components |μa| =1.240(2), |μb| = 0.588(10) and |μc| = 0.278(8) D. A model calculation to reproduce the ground state rotational constants indicates that the data are consistent with a twisted ring conformation. The average intensity ratio gives vibrational separations between the ground and excited states of the ring-bending and ring-twisting modes of ~ 178 and ~ 277 cm-1 respectively.

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