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Spectroscopic detection of terrestrial deuterium
Author(s) -
Krasnopolsky Vladimir A.
Publication year - 1998
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/98gl01654
Subject(s) - deuterium , mars exploration program , analytical chemistry (journal) , absorption (acoustics) , isotope , physics , ion , kinetic isotope effect , photodissociation , chemistry , atomic physics , astrobiology , nuclear physics , optics , photochemistry , chromatography , quantum mechanics
Observation of Mars at 1212–1218 Å with the HST Goddard high‐resolution spectrograph revealed both Mars' and Earth's D Ly‐α lines. The telluric line intensity is 17±4 R (Rayleighs) at 600 km. We construct a model for H 2 , H, HD, and D from 85 to 500 km with escape velocities V H and V D as the model parameters. D is formed by photolysis of HDO and in reactions of HD with O, O + , and O(¹D). The calculated intensity at solar minimum (F 10 7 cm = 70, T ∞ = 736 K) agrees with the measured value for V D = 80±15 cm/s. We applied our model to previous detections of deuterium by means of deuterium absorption cells and ion mass spectrometry. Escapes of H and D are diffusion limited, isotope fractionation factor is 0.88, and deuterium enrichment in the escape processes is ineffective.