On the sodium D line emission in the terrestrial nightglow

摘要: Abstract Emission from atomic Na, consisting of a doublet lines at 589.0 and 589.6 nm, is prominent feature the earth’s nightglow. A large data-base measurements relative intensities D (RD) was gathered three locations: ALOMAR observatory, Andenes (Norway, 69°N), Kuujjuarapik (Canada, 55°N) Danum Valley (Borneo, 8°N). RD varies between 1.5 2.0, with an average value 1.67. These results were interpreted using theoretical model Na nightglow which involves initial production electronically excited NaO(A2Σ) reaction O3, followed either by O to generate Na(2PJ) branching ratio 1/6 J=3/2 1/2 propensity or quenching NaO(A) NaO(X2Π) O2. The resulting NaO(X) then reacts 1.5. ratios spin-orbit propensities are derived statistical correlation electronic potential energy surfaces connecting reactants NaO(A)+O NaO(X)+O products Na+O2, through Na+O2− ion-pair intermediate. fit this earlier laboratory study ( Slanger et al., 2005 ), where measured as function [O]/[O2], indicates that rate coefficient for O2 around 1×10−11 cm3 molecule−1 s−1. also in good accord recent high resolution observations line widths Harrell 2010 ). An atmospheric used show gravity wave-driven perturbations layer can account observed variability RD.