Kinetic study of neutral lead cluster reactions

Abstract

Abstract. Kinetic studies of the reactions of neutral lead clusters with NO2, NO and 02 were performed at 300 K. Reaction with NO2 is rapid, with the observed second-order rate constants for most clusters being between 0.2 and 5 x 10 -11 cm3/s. There is a general trend of increasing rate with cluster size, although a few clusters display unusually high or low rates compared to ones of neighboring size. The reactions with NO are considerably slower by factors ranging from about 5 to 10. Reaction products are observed by laser ionization at 193 and 222 nm in conjunction with time-of-flight mass spectrometry. At lower fluence, the association products Pbx(NO2) + and Pbx(NO2)] are observed in the case of reactions with NO 2. At higher laser fluence, Pbx ~ and PbxO~ + I dominate the mass spectra of Pb~ reactions with NO2, showing that the products fragment to more stable oxides. No reaction with oxygen was observed for any cluster, setting upper limits on the rates of 5 × 10 '14 cm3/s.

Structures and Stabilities of Pbn (n ≤ 20) Clusters

“…Experimental studies − on lead clusters so far include the measurements of dissociation energies, mass spectra, ionization potentials, photoelectron spectroscopy, electron affinities, and chemical reactivity. Theoretically, Lai et al studied the structures of Pb n clusters in the size range of 3 < n < 56 by using the n -body Gupta potential to account for the interactions between the atoms in clusters.…”

Study of hail density parametrizations

“…) and other areas. In consequence it has an important effect in cloud simulation models (Farley 1987;Straka 1989).…”

“…) while, in others, applications are found of the equation proposed by PP (among them, Heymsfield 1983;Miller et al 1988Miller et al , 1990 or by Levi and Lubart (1991) (Castellano et al 1994;Nasello and Castellano 1998, etc.). Also, in problems related to convective cloud models including hail growth microphysics, Farley (1987) applied M's parametrization while Straka (1989) applied that of PP. Similarly, variations of the ρ(X) expression used can be found in models where the growth of accreted ice on electric cables or aeroplane wings is simulated (Makkonen and Stalabrass 1984, etc.…”

Structures of Pbn(n= 21–30) clusters from first-principles calculations

“…Experimental studies [22][23][24][25][26][27][28][29][30] on lead clusters include the measurements of ion mobility, dissociation energy, mass spectra, ionization potential, photoelectron spectroscopy, electron affinity, and chemical reactivity. The experimental data can only give indirect information about the structures of clusters, and the structures inferred from the experimental measurements need to be further verified by theoretical calculations.…”