Compound-negative-ion resonance states and threshold-electron excitation spectra of <i>N</i>-heterocyclic molecules: Pyridine, pyridazine, pyrimidine, pyrazine, and <i>sym</i>-triazine

Pisanias, M. N.; Christophorou, L. G.; Carter, J. G.; McCorkle, D.L.

doi:10.1063/1.1679477

Cited by 56 publications

(16 citation statements)

References 20 publications

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“…The lowest lying 3 B 1 triplet state of pyrimidine has been firmly located by observing laserinduced phosphorescence bands, which have an origin at 3.538 eV [13,14]. To observe the triplet states at higher energies the nearthreshold electron energy loss spectra were measured using the trapped electron technique [9,10]. The rather weak features in the excitation spectrum of Ref.…”

Section: Introductionmentioning

confidence: 99%

A study of the electronic states of pyrimidine by electron energy loss spectroscopy

Linert¹,

Zubek²

2015

Chemical Physics Letters

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Section: Introductionmentioning

confidence: 99%

A study of the electronic states of pyrimidine by electron energy loss spectroscopy

Linert¹,

Zubek²

2015

Chemical Physics Letters

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“…The valence excitation spectrum studied by visible-ultraviolet ͑VUV͒ photoabsorption 6,13 and by electron impact 5,13 is complex and has been interpreted in terms of transitions to the lowest energy singlet and triplet excited states involving the lowest energy unoccupied molecular orbital ͑LUMO͒ and the highest energy occupied molecular orbital ͑HOMO͒. The theoretical studies include MR-CI calculations 13 and Green's functions 8 methods.…”

Section: Introductionmentioning

confidence: 99%

“…The previous experimental studies of pyridine were devoted mainly to the negative ion resonances [3][4][5] and the valence excitation spectra 3,6,7 which are complex, difficult to interpret, and assigned in terms of transitions to the lowestenergy singlet and triplet electronic excited states. Ab initio calculations, using high level multireference Configuration interaction ͑MRCI͒ 3, 8 and Green's functions 9 were performed to interpret these data.…”

Section: Introductionmentioning

confidence: 99%

The core excitation of pyridine and pyridazine: An electron spectroscopy and ab initio study

Hannay

Duflot

Flament

et al. 1999

The Journal of Chemical Physics

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The carbon and nitrogen K-shell excitation spectra of gaseous pyridine and pyridazine were recorded using the electron-energy loss spectroscopy under electric-dipole conditions (2 keV, small angle) with a resolution of 0.2 eV. Ab initio Configuration interaction calculations in the frame of the equivalent core model were performed in order to help in the assignment of the spectral features. The spectra are dominated by the transitions to the 1π* and σ* type orbitals. The C1s spectra of both molecules are close to that of benzene: The intensity of Rydberg transitions are enhanced by an important valence σC–H* character; the 1s→3π* transition is mixed with double excitations and give rise to several states, some of them lying above the ionization thresholds. Finally, the N1s spectra of both molecules are similar to the s-triazine one.

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“…If Ereorg is the reorganization energy associated with changes in the N-electron system due to the captured electron, and AEcorr is the change in correlation energy, VAEm =EmN + Ereorg + AEcorr (10) In attempts to find out how well semiempirical approaches explain the experimental results on the NIR states of aromatic molecules, it was found that a qualitative relationship exists between the experimental positions of the NIRs and the CNDO virtual-orbital energies for benzene and substituted benzenes (5,8), and the theory was successful in predicting the number and relative positions of the negative ion states of these systems (5,(8)(9)(10)(11)(12)(13)(14)(15) (23).…”

Section: Short-lived Transient Negative Ionsmentioning

confidence: 99%

Negative ions of polyatomic molecules.

Christophorou¹

1980

Environ Health Perspect

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In this paper general concepts relating to, and recent advances in, the study of negative ions of polyatomic molecules are discussed with emphasis on halocarbons. The topics dealt with in the paper are as follows: basic electron attachment processes, modes of electron capture by molecules, short-lived transient negative ions, dissociative electron attachment to ground-state molecules and to "hot" molecules (effects of temperature on electron attachment), parent negative ions, effect of density, nature, and state of the medium on electron attachment, electron attachment to electronically excited molecules, the binding of attached electrons to molecules ("electron afflinity"), and the basic and the applied significance of negative-ion studies. Basic -Electron Attachment ProcessesThis paper deals with negative ions formed in electron-molecule collisions at low energies (<15 eV). Negative ions produced at higher energies (e.g., ion-pair processes) or in collisions of molecules with electronically-excited species (e.g., metastable atoms, Rydberg states) will not be discussed. The basic processes to be considered, then, can be classified as electron attachment to ground state molecules, to "hot" molecules, or to electronically excited molecules.Electron attachment to ground state molecules predominantly in their lowest state(s) of internal excitation may be represented by the scheme of Eqs. (1)

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Compound-negative-ion resonance states and threshold-electron excitation spectra of N-heterocyclic molecules: Pyridine, pyridazine, pyrimidine, pyrazine, and sym-triazine

Cited by 56 publications

References 20 publications

A study of the electronic states of pyrimidine by electron energy loss spectroscopy

A study of the electronic states of pyrimidine by electron energy loss spectroscopy

The core excitation of pyridine and pyridazine: An electron spectroscopy and ab initio study

Negative ions of polyatomic molecules.

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