A CROSSED MOLECULAR BEAM, LOW-TEMPERATURE KINETICS, AND THEORETICAL INVESTIGATION OF THE REACTION OF THE CYANO RADICAL (CN) WITH 1,3-BUTADIENE (C4H6). A ROUTE TO COMPLEX NITROGEN-BEARING MOLECULES IN LOW-TEMPERATURE EXTRATERRESTRIAL ENVIRONMENTS

作者：Morales Sebastien B; Bennett Christopher J; Le Picard Sebastien D^*; Canosa Andre; Sims Ian R; Sun B J; Chen P H; Chang Agnes H H; Kislov Vadim V; Mebel Alexander M; Gu Xibin; Zhang Fangtong; Maksyutenko Pavlo; Kaiser Ralf I

来源：Astrophysical Journal, 2011, 742(1): 26.

DOI：10.1088/0004-637X/742/1/26

• astrochemistry
• methods: laboratory
• molecular processes

We present a joint crossed molecular beam and kinetics investigation combined with electronic structure and statistical calculations on the reaction of the ground-state cyano radical, CN(X-2 Sigma(+)), with the 1,3-butadiene molecule, H2CCHCHCH2((XAg)-Ag-1), and its partially deuterated counterparts, H2CCDCDCH2(X(1)A(g)) and D2CCHCHCD2(X(1)A(g)). The crossed beam studies indicate that the reaction proceeds via a long-lived C5H6N complex, yielding C5H5N isomer(s) plus atomic hydrogen under single collision conditions as the nascent product(s). Experiments with the partially deuterated 1,3-butadienes indicate that the atomic hydrogen loss originates from one of the terminal carbon atoms of 1,3-butadiene. A combination of the experimental data with electronic structure calculations suggests that the thermodynamically less favorable 1-cyano-1,3-butadiene isomer represents the dominant reaction product; possible minor contributions of less than a few percent from the aromatic pyridine molecule might be feasible. Low-temperature kinetics studies demonstrate that the overall reaction is very fast from room temperature down to 23 K with rate coefficients close to the gas kinetic limit. This finding, combined with theoretical calculations, indicates that the reaction proceeds on an entrance barrier-less potential energy surface (PES). This combined experimental and theoretical approach represents an important step toward a systematic understanding of the formation of complex, nitrogen-bearing molecules-here on the C5H6N PES-in low-temperature extraterrestrial environments. These results are compared to the reaction dynamics of D1-ethynyl radicals (C2D; X-2 Sigma(+)) with 1,3-butadiene accessing the isoelectronic C6H7 surface as tackled earlier in our laboratories.

• 出版日期2011-11-20
• 单位东华大学