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

• Published in: Surveys in geophysics 2014-03, Vol.35 (2), p.259-334
• Main Author: Pavlov, A. V.
• Format: Article
• Language: English
• Subjects: Altitude; Astronomy; Atmospheric chemistry; Carbon dioxide; Density; Earth and Environmental Science; Earth Sciences; Freshwater; Geophysics; Geophysics/Geodesy; Ionosphere; Ions; Mass spectrometers; Mathematical analysis; Nitrogen dioxide; Observations and Techniques; Photochemistry; Photodetachment; Solar radiation; Studies
• ISSN: 0169-3298; 1573-0956
• DOI: 10.1007/s10712-013-9253-z

The current state of knowledge of the D-region ion photochemistry is reviewed. Equations determining production rates of electrons and positive ions by photoionization of atmospheric neutral species are presented and briefly discussed. Considerable attention is given to the progress in the chemistry of O + ( 4 S), O + ( 2 D), O + ( 2 P), N + , N 2 + , O 2 + , NO + , N 4 + , O 4 + , NO + (N 2 ), NO + (CO 2 ), NO + (CO 2 ) 2 , NO + (H 2 O) n for n  = 1–3, NO + (H 2 O)(N 2 ), NO + (H 2 O) 2 (N 2 ), NO + (H 2 O)(CO 2 ), NO + (H 2 O) 2 (CO 2 ), O 2 + (H 2 O), H 3 O + (OH), H + (H 2 O) n for n  = 1–8, O − , O 2 − , O 3 − , O 4 − , OH − , CO 3 − , CO 4 − , NO 2 − , NO 3 − , ONOO − , Cl − , Cl − (H 2 O), Cl − (CO 2 ), HCO 3 − , CO 3 − (H 2 O), CO 3 − (H 2 O) 2 , NO 3 − (H 2 O), NO 3 − (H 2 O) 2 , OH − (H 2 O), and OH − (H 2 O) 2 ions. The analysis of the D-region rocket ion mass spectrometer measurements shows that, among these ions, O 2 + , NO + , NO + (H 2 O), and H + (H 2 O) n for n  = 1–7 can make the main contribution to the total positive ion number density, and O − , O 2 − , Cl − , OH − (H 2 O), CO 3 − , HCO 3 − , NO 3 − , ONOO − , CO 4 − , NO 3 − (H 2 O), NO 3 − (H 2 O) 2 , and 35 Cl − (CO 2 ) ions can be responsible for the main contribution to the total negative ion number density. Photodetachment of electrons from O − , Cl − , O 2 − , O 3 − , OH − , NO 2 − , and NO 3 − , dissociative electron photodetachment of O 4 − and OH − (H 2 O), and photodissociation of O 3 − , O 4 − , CO 3 − , CO 4 − , ONOO − , HCO 3 − , CO 3 − (H 2 O), NO 3 − (H 2 O), O 2 + (H 2 O), O 4 + , N 4 + , NO + (H 2 O), NO + (H 2 O) 2 , H + (H 2 O) n for n  = 2–4, NO + (N 2 ), and NO + (CO 2 ) are studied, and the photodetachment and photodissociation rate coefficients are calculated using the current state of knowledge on the cross sections of these processes and fluxes of solar radiation.