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Unformatted text preview: process: C + + H 2--> CH 2 + + h ν Use the quantum RRK approach. For this reaction, the radiative stabilization step is rather fast: k r = 10 6 s-1 . The bond energy is about 4.3 eV (1 eV of energy corresponds to 8065 cm-1 after division by hc) , and the average frequency of the complex is 2000 cm-1 (s=3). 4. Assuming that H atoms do not react on grain surfaces, calculate the average number of H atoms per grain at steady state in a dense cloud at 10 K and at 20 K by considering accretion and thermal desorption processes. You may assume that the gas-phase H atom concentration is 1 cm-3 . What does your answer say about the possible efficiency of H 2 formation at the two temperatures? Use the silicate binding energy E D /k = 373 K....
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This note was uploaded on 06/13/2011 for the course CHEMISTRY 740 taught by Professor Herbst during the Winter '08 term at Ohio State.
- Winter '08