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Title: A UNIFIED MICROSCOPIC-MACROSCOPIC MONTE CARLO SIMULATION OF GAS-GRAIN CHEMISTRY IN COLD DENSE INTERSTELLAR CLOUDS

Abstract

For the first time, we report a unified microscopic-macroscopic Monte Carlo simulation of gas-grain chemistry in cold interstellar clouds in which both the gas-phase and the grain-surface chemistry are simulated by a stochastic technique. The surface chemistry is simulated with a microscopic Monte Carlo method in which the chemistry occurs on an initially flat surface. The surface chemical network consists of 29 reactions initiated by the accreting species H, O, C, and CO. Four different models are run with diverse but homogeneous physical conditions including temperature, gas density, and diffusion-barrier-to-desorption energy ratio. As time increases, icy interstellar mantles begin to grow. Our approach allows us to determine the morphology of the ice, layer by layer, as a function of time, and to ascertain the environment or environments for individual molecules. Our calculated abundances can be compared with observations of ices and gas-phase species, as well as the results of other models.

Authors:
 [1];  [2]
  1. Department of Chemistry, University of Virginia, Charlottesville, VA 22904 (United States)
  2. Also at Departments of Astronomy and Physics, University of Virginia, Charlottesville, VA 22904, USA. (United States)
Publication Date:
OSTI Identifier:
22086381
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 759; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTRONOMY; ASTROPHYSICS; CARBON MONOXIDE; CHEMISTRY; COMPUTERIZED SIMULATION; DENSITY; DESORPTION; DIFFUSION BARRIERS; ELEMENT ABUNDANCE; ICE; INTERSTELLAR SPACE; LAYERS; MOLECULES; MONTE CARLO METHOD; MORPHOLOGY; STOCHASTIC PROCESSES; TIME DEPENDENCE

Citation Formats

Chang Qiang, and Herbst, Eric. A UNIFIED MICROSCOPIC-MACROSCOPIC MONTE CARLO SIMULATION OF GAS-GRAIN CHEMISTRY IN COLD DENSE INTERSTELLAR CLOUDS. United States: N. p., 2012. Web. doi:10.1088/0004-637X/759/2/147.
Chang Qiang, & Herbst, Eric. A UNIFIED MICROSCOPIC-MACROSCOPIC MONTE CARLO SIMULATION OF GAS-GRAIN CHEMISTRY IN COLD DENSE INTERSTELLAR CLOUDS. United States. doi:10.1088/0004-637X/759/2/147.
Chang Qiang, and Herbst, Eric. Sat . "A UNIFIED MICROSCOPIC-MACROSCOPIC MONTE CARLO SIMULATION OF GAS-GRAIN CHEMISTRY IN COLD DENSE INTERSTELLAR CLOUDS". United States. doi:10.1088/0004-637X/759/2/147.
@article{osti_22086381,
title = {A UNIFIED MICROSCOPIC-MACROSCOPIC MONTE CARLO SIMULATION OF GAS-GRAIN CHEMISTRY IN COLD DENSE INTERSTELLAR CLOUDS},
author = {Chang Qiang and Herbst, Eric},
abstractNote = {For the first time, we report a unified microscopic-macroscopic Monte Carlo simulation of gas-grain chemistry in cold interstellar clouds in which both the gas-phase and the grain-surface chemistry are simulated by a stochastic technique. The surface chemistry is simulated with a microscopic Monte Carlo method in which the chemistry occurs on an initially flat surface. The surface chemical network consists of 29 reactions initiated by the accreting species H, O, C, and CO. Four different models are run with diverse but homogeneous physical conditions including temperature, gas density, and diffusion-barrier-to-desorption energy ratio. As time increases, icy interstellar mantles begin to grow. Our approach allows us to determine the morphology of the ice, layer by layer, as a function of time, and to ascertain the environment or environments for individual molecules. Our calculated abundances can be compared with observations of ices and gas-phase species, as well as the results of other models.},
doi = {10.1088/0004-637X/759/2/147},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 759,
place = {United States},
year = {2012},
month = {11}
}