Vibrational and electronic contributions to the polarizability and first hyperpolarizability of monosubstituted acetylene: Theoretical study

Abstract

AbstractThe two contributions, vibrational and electronic, to the electrical properties polarizability and first hyperpolarizability of monosubstituted acetylene HCCX (with X = F, Cl, Br, OH, SH, BH2, NH2, CH3, and SiH3) have been evaluated using the self‐consistent field wave functions within the double‐harmonic oscillator approximation. The results show that both contributions to the electrical properties are sensitive to the nature of the substituent: electronegativity, atomic volume, and X‐weight. In some cases, X = NH2, SiH3, and SH, the nonlinear optical response is essentially due to, and only to, the vibrational response β of the molecule. A complete study is made upon two tracks, upon the intrinsic properties of X and upon the IR and Raman spectra as well as the sum‐over‐modes expression. We also calculated the electrical properties at the AUG‐cc‐pVDZ basis set and at geometric parameters optimized at different levels of theory (B3LYP and MP2). © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004