Dissertation
Dissertation > Mathematical sciences and chemical > Physics > Molecular physics, atomic physics > Molecular Physics > Molecular spectroscopy

The Theoretical Prediction of Isomers and Infrared Spectrum of Interstellar Molecule SiC4H

Author WangLi
Tutor LiYouCheng;LiuYing
School Hebei Normal
Course Condensed Matter Physics
Keywords Interstellar molecules Density functional theory Infrared Spectroscopy
CLC O561.3
Type Master's thesis
Year 2009
Downloads 19
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Research and exploration of the interstellar molecules for the late stage of stellar evolution, the structure of the Milky Way and the origin of life is of great significance. , Including nitrile, acetylene derivatives, acetaldehyde, methanol, ether, ketone, ethanol and other complex organic compounds, including interstellar molecules has been recognized with more than 140 species; sugar and sugar derivatives found in meteorites from space thereof; interstellar space glycine (Gly) evidence has also been proposed. In recent years, important findings and discussion of the organic molecules in the nebula rich knowledge of the formation of interstellar molecules, and also make people have a new way of thinking about the evolution of life in the universe. Find new and complex organic interstellar molecules become the focus of attention of astronomers. The chain molecules SiCn the found-induced interest in such interstellar molecules. The researchers found in the IRC 10216 lapping layer SiCN (n = 1-4) of the spectral characteristics and structure for SiCN (n = 3-8), isomers and Spectroscopy theoretical predictions are also widely deployed. Based on density functional theory, GGA-BLYP exchange-correlation functions and polarization functions augmented double numerical atomic basis set DNP, carried out an extensive search may of interstellar molecules SiC4H of the isomers; and in the DFT / B3LYP/6-311 G (d, p) level SiC4H isomers structure, dipole moment, rotational constants, vibrational frequencies, infrared strength further calculated to obtain the following results: 1) obtained 29 SiC4H isomers, wherein the plane of straight chain structure SiC4H-1-1 is the most stable; 2) Print straight chain structure SiC4H-1-1 in the infrared band characteristic spectrum (intensity) 495 (22) , 547 (69), 721 (37), 3470 (172), in units of cm-1 (km / mol); 3) SiC4H-2-1, SiC4H-3-1, SiC4H-3-3, SiC4H-6 -2 SiC4H-6-4 exists a high dipole moment, and easy to be detected. They are in the infrared band characteristic of the spectrum (intensity) were: SiC4H-2-1: 428 (102) 1031 (23) 1268 (128) 1548 (306) 1954 (560); SiC4H-3-1: 388 (46), 715 (49), 769 (35), 1013 (20), 1974 (431); SiC4H-3-3: 228 (31), 229 (22), 682 (28), 757 (64) , 970 (52), 982 (113), 1963 (768); SiC4H-6-2: 349 (25), 597 (75), 702 (41), 761 (32), 790 (55), 1876 (458 ), 2098 (104), 3450 (68); SiC4H-6-4: 238 (27), 447 (74), 598 (127), 1819 (151), 2073 (88), 2110 (1193).

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