The Chemistry of Star-Forming Regions

Abstract

David A. Williams was born in 1937 in Nottingham, U.K., educated at Queen's University Belfast (B.Sc., Ph.D.); he obtained a D.Sc. from the University of Manchester in 1980. He established a molecular astrophysics group at UMIST, Manchester, formerly was a professor at UMIST 1984-1994 and currently is Perren Professor of Astronomy at University College London. Current interests include cosmic dust. Thomas W. Harquist was born 1954 in Redwood City, CA, and was eduated Rice University (B.A.) and Harvard University (M.A., Ph.D.). He was a postdoc at Harvard, a Royal Society Jaffe ´Donation Fellow in University College London, assistant professor University of Maryland, senior research scientist MPI fuer extraterrestrische Physik, and lecturer University of Leeds, U.K. His main interest is diffuse astrophysical media.

A study of interstellar aldehydes and enols as tracers of a cosmic ray-driven nonequilibrium synthesis of complex organic molecules

“…H + CO → HCO, [5] CH 3 + HCO → ½CH 3 CHO * , [6] CH 3 CHO → CH 2 = CHðOHÞ, [7] ½CO-C 2 H 6 → ½C 2 H 5 CHO * → C 2 H 5 CHO, [8] C 2 H 6 → C 2 H 5 + H, [9] H + CO → HCO, [10]…”

“…1)--predicting abundances which are lower by several orders of magnitude compared with observations toward hot molecular cores like Sagittarius B2(N) (4). Because COMs constitute more than one-third of all detected interstellar molecules--among them vital precursors to molecular building blocks of life such as the sugar glycolaldehyde (HCOCH 2 OH) (5)--the elucidation of their formation routes will unravel the most fundamental processes that drive the hitherto poorly understood interstellar organic chemistry (6) and define the molecular complexity of organic molecules, which can be synthesized in our galaxy (7), thus ultimately predicting where else in the universe the molecular precursors to the origins of life might be synthesized (8). Origins of life can be summarized as the events producing living systems from nonliving systems (9).…”

Ice structures, patterns, and processes: A view across the icefields

“…Molecules in the interstellar medium are present in giant interstellar clouds that are cold and tenuous (Williams and Hartquist, 1999;Williams and Herbst, 2002). As mentioned above, such clouds, which are composed of gas and dust, are broadly divided into two classes: diffuse and dense.…”

Thermal Reactions of Oxygen Atoms With Alkenes at Low Temperatures on Interstellar Dust

“…Despite the overwhelming abundance of hydrogen, interstellar clouds have a rich, complex, and widely speciated chemistry, as evidenced by the over 150 molecules detected to date in the ISM (Burke & Brown;Lattelais et al 2010). The abundances of many of these interstellar molecules cannot be explained solely by chemical synthesis in the gas phase, and it is now widely accepted that reactions at the surfaces of interstellar dust grains play an important role in the formation mechanisms of many interstellar molecules (see Burke & Brown;Cuppen & Herbst 2007;Tielens 2005;Williams & Hartquist 1999;Williams & Herbst 2002, and references therein). However, due to the low temperatures of interstellar dust grains (typically 10 K; Snow & McCall 2006) chemical reactions of thermalized surface species, so-called thermal synthetic routes, can only proceed via pathways with very low or non-existent reaction barriers.…”