Electronic excitation and oscillator strength of ethyl bromide by vacuum ultraviolet photoabsorption and electron energy loss spectroscopy

The high resolution vacuum ultraviolet photoabsorption spectrum of ethyl bromide has been recorded between 5 and 10.15 eV (248-122 nm) using synchrotron radiation. It exhibits a broad structureless valence band centred at 6.1 eV of low cross section followed by a region dominated by excitation of Rydberg states. A high resolution photoelectron spectrum (PES) of the lowest energy ionization band has been obtained and provides ionization energies necessary for identification of related Rydberg-excited states. Also, analysis of the vibrational fine structure in the PES has allowed identification of the normal vibrational modes excited and their wave numbers in the ion. These data, in turn, have been used in the assignment of the lowest energy photoabsorption bands arising from electron excitation into the 5s Rydberg orbital. The electron energy loss spectrum, recorded from 6.5 to 14.1 eV, under electric-dipole conditions, confirms the magnitude of the photoabsorption cross-section values obtained using the synchrotron radiation and extends the differential and optical oscillator strength values up to 14.004 eV. (C) 2000 American Institute of Physics. [S0021-9606(00)01814-6]

Electronic excitation and optical cross-sections of methylamine and ethylamine in the UV and VUV

The high resolution ultraviolet (UV)-vacuum ultraviolet (VUV) photon absorption spectra of methylamine and ethylamine was discussed using synchrotron radiation. It was found that in methylamine, the energies of the absorption bands were centered at 5.7, 7.2 and 8.7 eV. The optical oscillator strengths of both molecules for the 5-14 eV energy range were also reported

Photoabsorption and near-threshold electron energy-loss spectroscopy of OClO

The spectroscopy of chlorine dioxide, OClO, has been investigated using the techniques of dissociative electron attachment (DEA), near-threshold electron energy loss (EEL, 0-10 eV) and optical absorption (2.5-10.8 eV). Mass and energy analyses of the ions formed in the DEA processes show that at energies above about 3 eV, the product ions are predominantly near-thermal Cl-, suggesting that the accompanying oxygen atoms are excited electronically. All features observed in the EEL experiments are in regions of optical absorption, indicating that the optically dark doublet and quartet states have energies which overlap optically allowed transitions. The optical spectrum itself is in good qualitative agreement with previous measurements, but there are differences in relative absorption cross sections. Alternative interpretations of some spectral features are proposed

Electronic excitation and oscillator strength of ethyl iodide by VUV photoabsorption and electron energy loss spectroscopy

A high resolution VUV photoabsorption spectrum of ethyl iodide has been recorded between 4 and 10.2 eV (310-120 nm) using synchrotron radiation. The spectrum consists of a broad structureless absorption band centered at 4.78 eV, followed by a region dominated by excitation of Rydberg states. A high resolution photoelectron spectrum (PES) of the lowest energy ionization band has been obtained and provides ionization energies necessary for identification of related Rydberg-excited states. Also, analysis of the vibrational fine structure in the PES has allowed identification of the normal vibrational modes excited and their wave numbers in the ion. These, in turn, have been used in the assignment of the lowest energy photoabsorption bands arising from electron excitation into the 6s Rydberg orbital. An electron energy loss spectrum has also been recorded from 5.8 to 14.2 eV, under electric-dipole conditions. It confirms the magnitude of the photoabsorption cross section values obtained using the synchrotron radiation and extends the differential and optical oscillator strength values up to 14.2 eV. © 1999 American Institute of Physics