Vibrational and Electronic Contributions to te Polarizability and First Hyperpolarizability of Monosubstituted Acetylene:Theoretical Study

摘要

The two contributions,vibratonal and electronic,to the electrical properties polarizability and first hyperpolarizability of monosubstituted acetylene HC(ident to)C-X (with X=F,Cl,Br,OH,SH,BH_2,NH_2,CH_3,and SiH_3)have ben evaluated using the self-consistent field wave functions within the double-harmonic oscillator aproximation.The results sow 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=NH_2,SiH_3,and SH,the nonlinear optical response is essentially due to,and only to,the vibrational response beta_L~v of the molecule.A complete study is made upon two tracks,upon the intrinsic properties of X adn upon the IR and Raman spectra as well as the sum-over-modes expression.We also calcualted the electrical properties at the AUG-cc-pVDZbasis set and at geometric parameters optimized at different levels of theory (B3LYP and MP2).