Atmospheric electron–ion and ion–ion recombination processes

Abstract

The electron-ion and ion-ion recombination processes of importance in the upper atmosphere are considered, and available laboratory experimental and theoretical information concerning the relevant processes is discussed. For atomic ions the principal electron-ion recombination process is radiative, with theory indicating that the two-body coefficient at -200 "K is -10-" cm3/s and decreases with increasing electron temperature. Microwave afterglow/mass spectrometer studies of diatomic ionospheric ions (e.g. NOf, 02f., and N Z f ) show a loss by dissociative recombination with a coefficient substantially in excess of cm3/s at 250 "K and decreasing with increasing electron and ion temperature. There is some evidence from flame studies that H 3 0 f ions exhibit a very large coefficient (10-6-10-5 cm3!s) at 300 OK. Ion-ion recombination evidently proceeds by mutual neutralization, with laboratory studies of ions such as NOf and NO2-indicating a two-body coefficient of the order of cm3/s at 300 OK. In the lower D region, three-body Thomson recombination may be important, since laboratory studies of "air" ions indicate a three-body coefficient of -2 x cm6/s at 300 OK.

Photochemistry of Ions at D-region Altitudes of the Ionosphere: A Review

“…Thus, in agreement with the generally accepted approach (see, e.g., Biondi 1969), termolecular mutual neutralization reactions between positive and negative ionospheric ions do not have to be included in ionospheric models of the D-region composition. Table 6 shows that the O ?…”

Observations of time dependence and aspect sensitivity of regions of enhanced UHF backscatter associated with RF heating

“…Djuth et al (1994) explained the descending EUS by enhanced electron concentration caused by reduced recombination due to the temperature increases. The recombination coefficient is a decreasing function of temperature (Biondi, 1969) and hence higher temperatures increase the level of reduced recombination. This is consistent with the results of Gurevich (1978), Jones et al (1982) and Robinson (1989), and also with Honary et al (1993), who found that chemical processes dominated over transport effects at lower altitudes.…”

Estimating the contribution of ion–ion recombination to sub-2 nm cluster concentrations from atmospheric measurements

“…The role of ion-ion recombination as a sink for air ions has been known for decades, and the rate of the process and its dependency on environmental conditions has been widely studied (e.g. Nolan, 1941;McGowan, 1965;Biondi, 1968;Bates, 1985;Hoppel and Frick, 1986;Sorokin and Mirabel, 2001;Tammet et al, 2006). More recently, researchers have also attempted to estimate the importance of ion-ion recombination for atmospheric new particle formation (e.g.…”