A kinetic study of reactions of calcium-containing molecules with O and H atoms: implications for calcium chemistry in the upper atmosphere.

This paper describes the kinetic study of a number of gas-phase reactions involving neutral Ca-containing species, many of which are important for describing the chemistry of meteor-ablated calcium in the Earth's upper atmosphere. Ca atoms were produced thermally in the upstream section of a fast flow tube, and then converted to the molecular species CaO, CaO(2), CaO(3), CaCO(3) or Ca(OH)(2) by the addition of appropriate reagents. Atomic O or H was added further downstream, and both Ca and CaO were detected at the downstream end of the flow tube by laser-induced fluorescence.

A kinetic study of the reactions of Ca+ ions with O3, O2, N2, CO2 and H2O.

The reactions between Ca(+)(4(2)S(1/2)) and O(3), O(2), N(2), CO(2) and H(2)O were studied using two techniques: the pulsed laser photo-dissociation at 193 nm of an organo-calcium vapour, followed by time-resolved laser-induced fluorescence spectroscopy of Ca(+) at 393.37 nm (Ca(+)(4(2)P(3/2)-4(2)S(1/2))); and the pulsed laser ablation at 532 nm of a calcite target in a fast flow tube, followed by mass spectrometric detection of Ca(+). The rate coefficient for the reaction with O(3) is essentially independent of temperature, k(189-312 K) = (3.