Li+ ion affinities of global-warming perfluorocarbons

Density functional theory studies were performed for the first time to obtain the Li+ ion affinities of various perfluorocarbons (PFCs) that cause global-warming. Becke's three-parameter hybrid density functional, B3LYP combined with 6-31G(d), 6-311+G(2d), and 6-311+G(3df) basis sets were utilized for this purpose. We present optimized geometries of PFC-Li+ ion complexes at B3LYP/6-311+G(2d) level. The frequencies obtained at the same level were used to verify all the optimized geometries are minima. The following PFCs-CF4, CHF3, CH2F2, CH3F, C2F6, C4F8, with SF6-were considered in the present study. The calculated Lif affinities for CF4, CHF3, CH2F2, CH3F, C2F6, C4F8, and SF6 are 12.31, 19.64, 26.84, 30.10, 17.20, 21.09, and 16.92 kcal/mol, respectively at B3LYP/6-311+G(3df) after zero-point energy and thermal energy corrections. The large Li+ affinities indicate the validity of our proposed Li+ ion attachment mass spectrometry to quantify the emission of these greenhouse gases from semiconductor industries. Complex geometries were obtained and the ion-molecular bonding nature was discussed on the basis of atomic charge, electron density rho, and its Laplacian.