Rubén Delgado1, Yasuyuki Ishikawa1, Brad R. Weiner1 and Jonathan S. Friedman2

1Department of Chemistry, University of Puerto Rico, Río Piedras, PR 00931
2Arecibo Observatory, National Astronomy and Ionosphere Center, HC3 Box 53995 Arecibo, PR 00612

Ab initio calculations were performed to estimate the reaction enthalpies of species that may be involved in the formation of Atomic metal Enhanced Layers (ALE’s) in the upper mesosphere and lower thermosphere in the region of 80 to 100 km. Among the mechanisms proposed in the formation of ALE’s in the upper atmosphere are dissociative electron attachment and meteoric ablation. Minimum equilibrium geometry and harmonic frequencies for each structure associated with the enhancement of the sodium (Na) and potassium (K) layers were determined by second order Møller-Plesset (MP2) electron correlation method. The ab initio energies for all the molecules and atoms involved were determined by fourth order Møller-Plesset theory (MP4). Accurate total energies for NaHCO3, NaCO3, NaAlSiH4, NaSiO3, their potassium analogs and respective anions, products and transition state structures are determined by employing the G-2 method. Lidar observations of the K layers between 85 and 110 km were carried out to obtain temperature profiles of the layers through Doppler measurements tuned to the D1 fine structure line. Temperature profiles will allow us to establish the chemical reaction rate constants and will provide insight into the stability of these reaction products.