Absolute vacuum ultraviolet absorption spectra of some gaseous azabenzenes

Bolovinos, A.; Tsekeris, P.; Philis, John G.; Pantos, E.; Andritsopoulos, G.

doi:10.1016/0022-2852(84)90051-1

Cited by 195 publications

(250 citation statements)

References 45 publications

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“…Here either one or two Gaussian functions were employed as fitting functions for each spectral feature, with the positions and widths of each feature having been established through consideration of the available photo-absorption spectra, 3,[21][22][23] threshold-electron excitation spectra, 23 and theoretical calculations. [22][23][24] A full discussion of the present spectral assignments has been reported in our earlier paper 17 relating to the ICS, so we do not repeat those details here.…”

Section: Experimental Methods and Analysismentioning

confidence: 99%

“…3,[21][22][23] In particular, the photo-absorption studies on pyrimidine, in combination with benzene and other azabenzenes, 21 have provided key insights into how the introduction of N atoms into the benzene ring influences the nature of the n-π * and π -π * transitions. These experiments have been interpreted with the assistance of numerous theoretical calculations to provide a detailed understanding of the singlet electronic states.…”

Section: Physical Properties and Excited Electronic State Spectromentioning

confidence: 99%

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Differential cross sections for the electron impact excitation of pyrimidine

Jones

Bellm

Blanco

et al. 2012

The Journal of Chemical Physics

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We report on differential cross section (DCS) measurements for the electron-impact excitation of the electronic states of pyrimidine. The energy range of the present measurements was 15-50 eV with the angular range of the measurements being 10 • -90 • . All measured DCSs displayed forward-peaked angular distributions, consistent with the relatively large magnitudes for the dipole moment and dipole polarizability of pyrimidine. Excitations to triplet states were found to be particularly important in some energy loss features at the lower incident electron energies. To the best of our knowledge there are no other experimental data or theoretical computations against which we can compare the present results.

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Section: Experimental Methods and Analysismentioning

confidence: 99%

Section: Physical Properties and Excited Electronic State Spectromentioning

confidence: 99%

Differential cross sections for the electron impact excitation of pyrimidine

Jones

Bellm

Blanco

et al. 2012

The Journal of Chemical Physics

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“…The remaining EEL features at 4.3, 5.2, 5.8, and 6.5 eV were all assigned to π → π* transitions to states of symmetry 3 A 1 , 3 B 2 with 3 A 1 , 3 B 2 , and 3 B 2 along with 3 A 1 , respectively. The most intense maximum at 7.6 eV was found to correspond to both 1 B 2 and 1 A 1 transitions, as in the vacuum ultraviolet (VUV) spectra (Bolovinos et al 1984).…”

Section: Pyrimidinementioning

confidence: 96%

Measurement of inelastic cross sections for low-energy electron scattering from DNA bases

Michaud¹,

Bazin²,

Sanche³

2011

International Journal of Radiation Biology

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Purpose-Determine experimentally the absolute cross sections (CS) to deposit various amount of energies into DNA bases by low-energy electron (LEE) impact.Materials and methods-Electron energy loss (EEL) spectra of DNA bases are recorded for different LEE impact energies on the molecules deposited at very low coverage on an inert argon (Ar) substrate. Following their normalisation to the effective incident electron current and molecular surface number density, the EEL spectra are then fitted with multiple Gaussian functions in order to delimit the various excitation energy regions. The CS to excite a molecule into its various excitation modes are finally obtained from computing the area under the corresponding Gaussians.Results-The EEL spectra and absolute CS for the electronic excitations of pyrimidine and the DNA bases thymine, adenine, and cytosine by electron impacts below 18 eV are reported for the molecules deposited at about monolayer coverage on a solid Ar substrate.Conclusions-The CS for electronic excitations of DNA bases by LEE impact are found to lie within the 10 −16 -10 −18 cm 2 range. The large value of the total ionisation CS indicates that ionisation of DNA bases by LEE is an important dissipative process via which ionising radiation degrades and is absorbed in DNA.

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“…Three Al states (two 1T1T* states and a Ryd-berg state) are thought to lie in close proximity between 207 and 182 nm. 37 These modes can also derive intensity by preresonance enhancement of the A term, as described by Eq. ( 16), and may become more prominent with excitation at shorter wavelength.…”

Section: Hyper-raylelgh Scatteringmentioning

confidence: 99%

Nonresonant hyper-Raman and hyper-Rayleigh scattering in benzene and pyridine

Neddersen

Mounter

Bostick

et al. 1989

The Journal of Chemical Physics

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Nonresonant hyper-Raman and hyper-Rayleigh spectra excited at 1064 nm are reported for neat benzene and pyridine. The theory of Herzberg-Teller vibronic coupling in nonresonant and preresonant hyper-Raman scattering is developed. Nonresonant hyper-Raman scattering is shown to be vibronically induced by modes that efficiently couple strongly allowed onephoton and two-photon transitions. A weak and broad (55 cm -I) hyper-Rayleigh band was observed in benzene and attributed to collective scattering, while in pyridine, a much more intense and much narrower hyper-Rayleigh band was observed. Only the a 2u vibration (VII) was observed in the hyper-Raman spectrum of benzene, while several strong bands were observed in pyridine. Possible vibronic-coupling pathways are discussed for these modes. In addition, the observed hyper-Raman spectrum of pyridine is compared to a recent calculation.

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Absolute vacuum ultraviolet absorption spectra of some gaseous azabenzenes

Cited by 195 publications

References 45 publications

Differential cross sections for the electron impact excitation of pyrimidine

Differential cross sections for the electron impact excitation of pyrimidine

Measurement of inelastic cross sections for low-energy electron scattering from DNA bases

Nonresonant hyper-Raman and hyper-Rayleigh scattering in benzene and pyridine

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