Namazian, MansoorZakery, MaryamNoorbala, MohammadCoote, Michelle2015-12-100009-2614http://hdl.handle.net/1885/51309The pKa value of trifluoroacetic acid has been successfully calculated using high-level ab initio methods such as G3 and CBS-QB3. Solvation energies have been calculated using CPCM continuum model of solvation at the HF and B3-LYP levels of theory with various basis sets. Excellent agreement with experiment (to within 0.4 pKa units) was obtained using CPCM solvation energies at the B3-LYP/6-31+G(d) level (or larger) in conjunction with CBS-QB3 or G3 gas-phase energies of trifluoroacetic acid and its anion.Keywords: Calculations; Continuum mechanics; Negative ions; Solvation; Gas-phase; Initio calculations; Trifluoroacetic acid; Organic acids200810.1016/j.cplett.2007.11.0882015-12-09