“…As described previously, we have identified both CF 3 and I radicals in electron-stimulated desorption experiments. Formation of • CF 2 I radicals has been hypothesized previously in γ-radiolysis studies of liquid and gas-phase CF 3 I 39,40 and electron-induced chemistry of adsorbed CF 3 I. , Formation of difluorocarbene (:CF 2 ) has been previously postulated in the radiolysis of CF 3 I . Below we postulate several reaction mechanisms, involving the aforementioned intermediates, to explain the radiolysis of CF 3 I.…”
Section: Resultsmentioning
confidence: 64%
“…The parent peaks of CFI 3 ( m / z = 412), CF 2 I 2 ( m / z = 304), and C 2 F 4 I 2 ( m / z = 354) could not be monitored because the UTI model 100C mass spectrometer is only capable of monitoring mass fragments up to 300. Previous γ-radiolysis studies of CF 3 I have identified CF 2 I 2 , C 2 F 5 I, C 2 F 4 I 2 , and C 2 F 6 as radiolysis products of CF 3 I. − Our identification of CFI 3 , however, represents a new finding. 4 Postirradiation (40 eV electrons at a fluence of 2 × 10 15 cm -2 ) temperature-programmed desorption data of CF 3 I multilayers (four layers) showing the desorption of C 2 F 6 , C 2 F 5 I, CF 2 I 2 , C 2 F 4 I 2 , I 2 , and CFI 3 .…”
Section: Resultsmentioning
confidence: 67%
“…This procedure allowed for the detection of radiolysis product desorption peaks at temperatures above 160 K that would have been too small to detect in the presence of the large CF 3 I multilayer and monolayer peaks. In identifying the radiolysis products, the results of the postirradiation temperature-programmed desorption experiments were also compared to previously identified γ-radiolysis products − of CF 3 I: I 2 , CF 4 , C 2 F 6 , CF 2 I 2 , C 2 F 5 I, and C 2 F 4 I 2 . To further verify the identification of radiolysis products, the desorption temperature and boiling point trends of the radiolysis products were also compared.…”
Section: Resultsmentioning
confidence: 99%
“…Three different reaction channels can be proposed for the formation of CF 2 I 2 . The • CF 2 I radicals could abstract an iodine atom from molecular iodine (eq 6) or CF 3 I (eq 7), or react with atomic iodine (eq 8) C 2 F 5 I could be formed by a carbene insertion reaction (eq 9) or a radical−radical reaction (eq 10): …”
Section: Resultsmentioning
confidence: 99%
“…This procedure allowed for the detection of radiolysis product desorption peaks at temperatures above 160 K that would have been too small to detect in the presence of the large CF 3 I multilayer and monolayer peaks. In identifying the radiolysis products, the results of the postirradiation temperatureprogrammed desorption experiments were also compared to previously identified γ-radiolysis products [38][39][40][41][42][43][44] The results of postirradiation temperature-programmed desorption experiments discussed above do not provide evidence for CF 4 , a previously known γ-radiolysis product of CF 3 I. [38][39][40]43 The failure to identify CF 4 as a radiolysis product of CF 3 I may be attributed to a combination of three factors: (1) CF 4 does not have a parent peak (m/z ) 88) in its mass spectrum, (2) the other mass spectral fragments (CF 3 + , CF 2 + , CF + , and F + ) of CF 4 are also fragments of CF 3 I, 37 and (3) CF 4 has a lower desorption temperature than CF 3 I.…”
Section: B Identification Of Cf 3 Radicalsmentioning
The surface-induced and electron-induced chemistry of trifluoroiodomethane (CF3I), a potential replacement
for chlorofluorocarbons (CFCs) and chlorofluorobromocarbons (halons), were investigated under ultrahigh
vacuum conditions (p ∼ 1 × 10-10 Torr) on Mo(110). Results of temperature-programmed desorption (TPD)
experiments indicate that dissociative adsorption of CF3I leads only to nonselective decomposition on Mo(110), in contrast to reactions of CF3I on other metal surfaces. Desorption of CF3 radicals and atomic iodine
was detected mass spectrometrically during low-energy (10−100 eV) electron irradiation of four monolayer
thick films of CF3I condensed at 100 K. Results of postirradiation temperature-programmed desorption
experiments were used to identify CF2I2, C2F5I, C2F6, C2F4I2, and CFI3 as electron-induced reaction products
of CF3I. Except for CFI3, all of these electron-induced reaction products of CF3I have been previously identified
in γ-radiolysis studies, supporting our earlier claim that temperature-programmed desorption experiments
conducted following low-energy electron irradiation of multilayer thin films provide an effective method to
investigate the effects of high-energy radiation, including radical−radical reactions.
“…As described previously, we have identified both CF 3 and I radicals in electron-stimulated desorption experiments. Formation of • CF 2 I radicals has been hypothesized previously in γ-radiolysis studies of liquid and gas-phase CF 3 I 39,40 and electron-induced chemistry of adsorbed CF 3 I. , Formation of difluorocarbene (:CF 2 ) has been previously postulated in the radiolysis of CF 3 I . Below we postulate several reaction mechanisms, involving the aforementioned intermediates, to explain the radiolysis of CF 3 I.…”
Section: Resultsmentioning
confidence: 64%
“…The parent peaks of CFI 3 ( m / z = 412), CF 2 I 2 ( m / z = 304), and C 2 F 4 I 2 ( m / z = 354) could not be monitored because the UTI model 100C mass spectrometer is only capable of monitoring mass fragments up to 300. Previous γ-radiolysis studies of CF 3 I have identified CF 2 I 2 , C 2 F 5 I, C 2 F 4 I 2 , and C 2 F 6 as radiolysis products of CF 3 I. − Our identification of CFI 3 , however, represents a new finding. 4 Postirradiation (40 eV electrons at a fluence of 2 × 10 15 cm -2 ) temperature-programmed desorption data of CF 3 I multilayers (four layers) showing the desorption of C 2 F 6 , C 2 F 5 I, CF 2 I 2 , C 2 F 4 I 2 , I 2 , and CFI 3 .…”
Section: Resultsmentioning
confidence: 67%
“…This procedure allowed for the detection of radiolysis product desorption peaks at temperatures above 160 K that would have been too small to detect in the presence of the large CF 3 I multilayer and monolayer peaks. In identifying the radiolysis products, the results of the postirradiation temperature-programmed desorption experiments were also compared to previously identified γ-radiolysis products − of CF 3 I: I 2 , CF 4 , C 2 F 6 , CF 2 I 2 , C 2 F 5 I, and C 2 F 4 I 2 . To further verify the identification of radiolysis products, the desorption temperature and boiling point trends of the radiolysis products were also compared.…”
Section: Resultsmentioning
confidence: 99%
“…Three different reaction channels can be proposed for the formation of CF 2 I 2 . The • CF 2 I radicals could abstract an iodine atom from molecular iodine (eq 6) or CF 3 I (eq 7), or react with atomic iodine (eq 8) C 2 F 5 I could be formed by a carbene insertion reaction (eq 9) or a radical−radical reaction (eq 10): …”
Section: Resultsmentioning
confidence: 99%
“…This procedure allowed for the detection of radiolysis product desorption peaks at temperatures above 160 K that would have been too small to detect in the presence of the large CF 3 I multilayer and monolayer peaks. In identifying the radiolysis products, the results of the postirradiation temperatureprogrammed desorption experiments were also compared to previously identified γ-radiolysis products [38][39][40][41][42][43][44] The results of postirradiation temperature-programmed desorption experiments discussed above do not provide evidence for CF 4 , a previously known γ-radiolysis product of CF 3 I. [38][39][40]43 The failure to identify CF 4 as a radiolysis product of CF 3 I may be attributed to a combination of three factors: (1) CF 4 does not have a parent peak (m/z ) 88) in its mass spectrum, (2) the other mass spectral fragments (CF 3 + , CF 2 + , CF + , and F + ) of CF 4 are also fragments of CF 3 I, 37 and (3) CF 4 has a lower desorption temperature than CF 3 I.…”
Section: B Identification Of Cf 3 Radicalsmentioning
The surface-induced and electron-induced chemistry of trifluoroiodomethane (CF3I), a potential replacement
for chlorofluorocarbons (CFCs) and chlorofluorobromocarbons (halons), were investigated under ultrahigh
vacuum conditions (p ∼ 1 × 10-10 Torr) on Mo(110). Results of temperature-programmed desorption (TPD)
experiments indicate that dissociative adsorption of CF3I leads only to nonselective decomposition on Mo(110), in contrast to reactions of CF3I on other metal surfaces. Desorption of CF3 radicals and atomic iodine
was detected mass spectrometrically during low-energy (10−100 eV) electron irradiation of four monolayer
thick films of CF3I condensed at 100 K. Results of postirradiation temperature-programmed desorption
experiments were used to identify CF2I2, C2F5I, C2F6, C2F4I2, and CFI3 as electron-induced reaction products
of CF3I. Except for CFI3, all of these electron-induced reaction products of CF3I have been previously identified
in γ-radiolysis studies, supporting our earlier claim that temperature-programmed desorption experiments
conducted following low-energy electron irradiation of multilayer thin films provide an effective method to
investigate the effects of high-energy radiation, including radical−radical reactions.
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