Surface abundance change in vacuum ultraviolet photodissociation of CO2 and H2O mixture ices.

Photodissociation of amorphous ice films of carbon dioxide and water co-adsorbed at 90 K was carried out at 157 nm using oxygen-16 and -18 isotopomers with a time-of-flight photofragment mass spectrometer. O((3)P(J)) atoms, OH (v = 0) radicals, and CO (v = 0,1) molecules were detected as photofragments. CO is produced directly from the photodissociation of CO(2).

Conversion of gaseous nitrogen dioxide to nitrate and nitrite on aqueous surfactants.

The hydrolytic disproportionation of gaseous NO(2) on water's surface (2 NO(2) + H(2)O → HONO + NO(3)(-) + H(+)) (R1) has long been deemed to play a key, albeit unquantifiable role in tropospheric chemistry. We recently found that (R1) is dramatically accelerated by anions in experiments performed on aqueous microjets monitored by online electrospray mass spectrometry. This finding let us rationalize unresolved discrepancies among previous laboratory results and suggested that under realistic environmental conditions (R1) should be affected by everpresent surfactants.