Spectroscopie d'électroionisation de HBr et DBr entre 11 et 25 eV

1985 ◽  
Vol 63 (8) ◽  
pp. 1015-1021 ◽  
Author(s):  
Paul Marmet ◽  
Hamid K. Nasrallah
Keyword(s):  
Rydberg States ◽  
Ionization Threshold ◽  
Negative Ion

Electroionization spectra of HBr and DBr are measured and analyzed between the ionization threshold and 25 eV. Several negative-ion states having configurations (4pσ) (4pπ)4 5s2, 5p2, and 4d2, associated with Rydberg states converging to the 2Σ+ limit, have been identified. Other structures result from the excitation of the inner 4sσ electron. Finally, data on DBr are used to confirm the interpretation.

scholarly journals Dissociative electron attachment in alcohols and ethers: Its relatioship to Rydberg states

2008 ◽  
Vol 6 (1) ◽  
pp. 77-88
Author(s):  
Bogdan Ibanescu ◽  
Michael Allan
Keyword(s):  
Excited State ◽  
Feshbach Resonance ◽  
Rydberg States ◽  
Electron Attachment ◽  
Dft Method ◽  
Negative Ion ◽  
Feshbach Resonances ◽  
Free Electrons ◽  
Potential Surfaces ◽  
Positive Ions

A dramatic difference was observed in the reactivity of alcohols and ethers toward free electrons. Whereas the lowest core-excited state of the negative ion - a 2(n,3s2) Feshbach resonance - of the alcohols readily dissociates by losing a hydrogen atom, ethers show no observable signal from this resonance. This difference in reactivity has a parallel in the anomalous shapes and energies of the parent states of the Feshbach resonances, the 1(n,3s) Rydberg states of the neutral alcohols and ethers. We explained this anomaly by means of potential surfaces of the alcohols and ethers calculated using the TD-DFT method as a function of the dissociation coordinate. The lowest excited state of alcohols was found to be repulsive, as a consequence of an avoided crossing between the 3s and 3px Rydberg configurations, whereas a barrier to dissociation was found in the ethers. Rydberg-valence mixing and avoided crossings are decisive in determining the shapes of the potential surfaces. It is concluded that the reactivities of alcohols and ethers toward free electrons are rationalized by assuming that the potential surfaces of the daughter Feshbach resonances closely follow those of the parent Rydberg states, i.e., the lowest Feshbach resonance is repulsive, but a barrier occurs in ethers. The potential surfaces of both the Rydberg states and the Feshbach resonances thus differ dramatically from the non-dissociative surface of the grandparent 2(n-1) positive ions, despite the nominally non-bonding character of the Rydberg electrons.

Structures observées dans la courbe d'émission photonique de N2 entre 11.00 et 15.50 eV

1977 ◽  
Vol 55 (24) ◽  
pp. 2134-2141 ◽  
Author(s):  
Paul Veillette ◽  
Pierre Marchand
Keyword(s):  
Electron Impact ◽  
Electron Energy ◽  
Incident Electron ◽  
Ionization Threshold ◽  
Negative Ion ◽  
Incident Electron Energy ◽  
Photon Yield

The measurement of the broadband photon yield of N2 molecules excited by electron impact, as a function of the incident electron energy, shows many structures below the ionization threshold. Most of them are due to the formation of negative ion resonances N2−.

The Electroionization Spectrum of Nitric Oxide

1974 ◽  
Vol 52 (19) ◽  
pp. 1885-1890 ◽  
Author(s):  
R. Carbonneau ◽  
P. Marmet
Keyword(s):  
Nitric Oxide ◽  
Rydberg States ◽  
Negative Ion ◽  
Electron Transmission ◽  
First Time ◽  
Π State

Negative ion resonances having the NO+b3Π, A1Π, c3Π, and B1Π states as grandparents are observed for the first time in the electroionization spectrum of NO. Our results are compared with those from electron transmission experiments. Moreover, some Rydberg states from the series converging to the NO+b3Π state have been analyzed.

Negative and Neutral Autoionizing States Detected in the Electroionization Curve in CO

1973 ◽  
Vol 51 (20) ◽  
pp. 2202-2208 ◽  
Author(s):  
R. Carbonneau ◽  
P. Marmet
Keyword(s):  
Excited States ◽  
Rydberg States ◽  
Negative Ion ◽  
Electron Transmission ◽  
Doubly Excited States ◽  
Doubly Excited ◽  
First Time ◽  
Autoionizing States

Negative ion resonances and neutral Rydberg states having the A2Π and B2Σ+ states of CO+ as limits are reported for the first time in the electroionization curve of CO. Moreover, new doubly excited states of CO are observed around 21 eV. The electroionization is compared with photoionization, photoabsorption, and electron transmission when data are available.

scholarly journals Laser Spectroscopic Investigation of High Rydberg States of no: Decay Dynamics Near the First Ionization Threshold

1994 ◽  
Vol 13 (3-4) ◽  
pp. 259-271 ◽  
Author(s):  
Asuka Fujii ◽  
Norio Morita
Keyword(s):  
Spectroscopic Investigation ◽  
Laser Excitation ◽  
Rydberg States ◽  
Decay Process ◽  
Ionization Threshold ◽  
Laser Spectroscopic

With a state-selective laser excitation, two main decay processes, autoionization and predissociation, in vibrational superexcited Rydberg states (n = 8–12, l = s, p, and f, v = 1) of NO have been studied, directly detecting not only NO+ ions generated by autoionization but also every fragment atom produced by predissociation. In addition, the v = 0 states lying below the ionization threshold have also been investigated with the same method, and the comparison between the two results has more clearly elucidated the competing behavior of the decay processes in the above-threshold states (v = 1). As a result, for the v = 1 state, it has been shown that predissociation is the main decay process in the np Rydberg states, while autoionization is dominant in the ns Rydberg states. For the nf Rydberg states, the N(4S) + O(3P) predissociation channel, which has not been emphasized in previous studies, has been found to play an important role in the decay dynamics both above and below the ionization threshold.

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