Heterogeneous Atom Oxygen Reactions on Mesospheric Dust and Ice Surfaces

Sri International, Menlo Park CA

Investigators

Abstract

The PI proposes to investigate oxygen atom reactions on dust and ice surfaces characteristic of particles in the mesosphere and lower thermosphere (MLT). Atomic oxygen is the most abundant reactive species in this altitude range, and its reactions on and with surfaces may contribute significantly to the chemistry in the MLT. Ice particles present in the mesosphere are observed as noctilucent clouds (NLCs), polar mesospheric clouds (PMCs), and polar mesospheric summer echoes (PMSEs). The initial reaction to be studied is the heterogeneous recombination of atomic oxygen on ice under conditions representative of the mesosphere (80-90 km) -a phenomenon suggested by recent rocket measurement of atomic oxygen profiles during NLC events. Other heterogeneous reaction schemes suggested in the literature that involve oxygen atom reactions with hydrogen molecules, oxygen molecules, and ice surfaces will then be explored. This proposal was submitted by the PI, Dr. Jochen Marschall, for James E. Boulter, a Ph.D. candidate in the Department of Chemistry at the University of Colorado, Boulder.