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Unformatted text preview: e investigated and it was found that the best anti –corrosion of Cu-P-SiC is at 5 g/L SiC concentration in the bath formulation. PHY-O4 RING-PUCKERING POTENTIAL ENERGY FUNCTIONS AND VIBRATIONAL REASSIGNMENTS FOR SOME SILACYCLOPENT-3-ENES Abdulaziz A. Al-Saadi Chemistry Department, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia E-mail: firstname.lastname@example.org The development of quantum chemical applications has recently provided a great help for spectroscopists in resolving some structural ambiguities when studying the molecular spectra of some cyclic silanes. We had utilized ab initio calculations to reinterpret previously reported far infrared spectra of silacyclopent-2-enes, and better assignments of the absorption lines of silacyclopent -2-ene and its 1,1-deuterated isotopomer were proposed. The vibrational spectra of the four -membered ring silacyclobutane and its 1,1-deuterated and 1,1-dihalo derivatives have been also revisited with the help of DFT calculations. In this study and as a continuation of reinvestigating the vibrational spectra of structurally interesting cyclic silanes, the ring -puckering potential energy functions and vibrational spectra of the symmetric five-membered ring silacyclopent-3-ene, its 1,1-d2, 1,1-difluoro and 1,1dichloro derivatives have been studied using standard ab initio molecular orbital theory and density functional theory calculations. We have utilized three density functionals (B95, BLYP and B3LYP) with several basis set to reinvestigate the previously rep orted infrared and Raman spectra of those symmetric cyclic silanes. The ring-puckering potential energy functions of the molecules were calculated and compared with each other. Comprehensive vibrational reassignments of the infrared and Raman spectra were also carried out. The ring-puckering potential energy function for silacyclopent -3-ene as obtained from B3LYP, B95 and MP2 levels turned out to be distinctly different. While silacylopent -3-ene is predicted by these levels of theory to be planar or almost nearly planar in agreement with 4 2 experimental work, the quadratic term contribution in the potential energy function: V(x) = ax – bx increases as going from B...
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- Spring '11