Synthesis of Cl2 induced by low energy (0–18 eV) electron impact to condensed 1,2-C2F4Cl2 molecules

Complete Chemical Transformation of a Molecular Film by Subexcitation Electrons (<3 eV)

“…3 shows a comparable set taken at 1 eV. As has been demonstrated by our recent work [15], irradiation of the C 2 F 4 Cl 2 film creates a new feature around 5 eV which is identified as Cl ÿ desorption from molecular chlorine. From our previous data an explicit relative cross section for the transformation of C 2 F 4 Cl 2 into Cl 2 versus electron energy could be extracted after irradiating the sample with a constant dosage of 10 C. This cross section showed two maxima, one below 2 eV and one near 10 eV with the value virtually dropping to zero at an energy near 4 eV.…”

“…All desorption spectra shown are calibrated with respect to the onset of the injection curve. Figure 1 shows a comparison of Cl ÿ formation from gas phase C 2 F 4 Cl 2 as previously reported from our laboratory [15] and the presently observed Cl ÿ desorption from a 5 monolayer C 2 F 4 Cl 2 film. In the gas phase, Cl ÿ is predominantly formed from two low energy features with the prominent one peaking at 0.3 eV.…”

“…In all these studies the reaction was observed at electron energies essentially above the threshold for electronic excitation and with the synthesized product often in minor amounts with respect to the initial molecule [5]. Of particular interest for the present results is a recent study on Cl 2 synthesis from condensed CF 2 Cl 2 [14] and from condensed C 2 F 4 Cl 2 [15]. In the latter case it was already demonstrated by our laboratory that Cl 2 synthesis is also operative at subexcitation energies.…”

“…Possible secondary pathways for Cl 2 synthesis may include polymerization of the radicals formed in the first step and also reactive scattering of Cl ÿ as discussed in Ref. [15]. From the thermodynamic point of view we have to consider the reaction…”

About energy balance during ESD processes in the very low range of electron energies: Measurements and discussion on the desorption of H− ions from a hydrogenated diamond film

“…However, during these last measurements the full electron dose received by the film should be kept low to limit as far as possible any charge trappings of electrons or ions within the physisorbed film. In the opposite condition, the kinetic energies and angular distributions of ions may be altered as well as the electron incident energies [7,19,20].…”