The x-ray emission spectrum of gaseous ethene

Carbon K-edge x-ray emission spectroscopy of gas phase ethylenic molecules

“…The series of lower energy emission lines were then attributed to transitions from the HOMO − 1 to HOMO − 4 to the same 1s energy level, with an energy progression that was approximately consistent with the valence energy level spacing reported by ultraviolet photoelectron spectroscopy [68]. The DFT-ROCIS calculations in this work (figure 4(a)) suggest that while the initial state for the four highest energy (Brammer, 1984) with NXES spectra upon 312.0 eV excitation of ethylene [44]. The literature data has been shifted to match the energy calibration in this work.…”

“…For ethylene, the symmetries of the four highest energy occupied orbitals are as follows: (2b 2u ) 2 (3a g ) 2 (1b 3g ) 2 (1b 3u ) 2 (see figure S1). In the previous EI study [44], the highest energy intense emission band was assigned to emission from the HOMO (1b 3u ) 2 to a hole formed in the 1s orbital following EI ionization. The series of lower energy emission lines were then attributed to transitions from the HOMO − 1 to HOMO − 4 to the same 1s energy level, with an energy progression that was approximately consistent with the valence energy level spacing reported by ultraviolet photoelectron spectroscopy [68].…”

“…The measured XAS spectra and accompanying calculations for the ethylenic systems studied suggest that the energy separation of the core levels should be resolvable in an XES experiment. The C K-edge XES spectrum of gaseous ethylene, recorded following EI ionization at an incident electron energy of 10 keV [44], is shown in figure 3 and is key for the validation of the photoexcitation methods used in this work. Overall, there is remarkably good agreement with the main features of the XES spectra following non-resonant x-ray excitation (at 312.0 eV).…”

“…Paradoxically, despite the interest in ethylenic systems, no such data is available on them to date. The only XES spectra of ethylenic systems in the gas phase that were reported have been obtained by electron impact (EI) excitation [16,44]. Here we combine carbon K-edge XAS with RXES and NXES, along with density-functional theory (DFT)-based computational methods to examine the core and valence electronic structure of three ethylenic systems in the gas phase (figure 1).…”

Core-electron shake-up spectra of polyenes: A theoretical study on size and site dependences and excitonic character

“…This seems also to hold for core-electron spectroscopies for which, in addition to shake-up, [9][10][11] one can find experimental and theoretical work for near-edge x-ray-absorption fine-structure spectra ͑NEXAFS͒, 5,12,13 x-ray emission, [14][15][16][17] and photoelectron shifts. 18,19 The x-ray photoelectron shake-up spectra have been presented in high resolution for the three first members of the polyene seriesethylene, butadiene, and hexatriene-in Refs.…”