TY - JOUR
T1 - Nonresonant frequency dispersion of the electronic second hyperpolarizability of all-trans polysilane chains
T2 - An ab initio TDHF oligomeric approach
AU - Champagne, Benoît
AU - Perpète, Éric A.
AU - André, Jean-Marie
PY - 1998/12/1
Y1 - 1998/12/1
N2 - The frequency-dependent electronic second hyperpolarizability of increasingly large polysilane chains is computed for the most common nonlinear optical (NLO) processes at the time-dependent Hartree-Fock level with the 6-31G atomic basis set. Due to σ-conjugation, the longitudinal component (γL
e) turns out to be dominant. Its nonresonant dispersion relations are described by the coefficients of the power expansion formula, γL
e[(-ωσ; ωa, ω2, ω3) = γL
e(0; 0, 0, 0)[1 + AωL
2 + BωL
4 + CωL
6 + ⋯], where ωL
2 = ωσ
2 + ω1
2 + ω2
2 + ω3
2 and γL
e(0; 0, 0, 0) is the static limit value. In the infinite chain length limit, the CHF/6-31G static longitudinal electronic second hyperpolarizability per Si2H4 unit cell is estimated to attain 463 ± 10 × 103 a.u. whereas the A coefficient reaches 27.8 ± 0.9 a.u. The accuracy that could be reached from using this power expansion expression for estimating the second hyperpolarizability for other optical frequencies is discussed.
AB - The frequency-dependent electronic second hyperpolarizability of increasingly large polysilane chains is computed for the most common nonlinear optical (NLO) processes at the time-dependent Hartree-Fock level with the 6-31G atomic basis set. Due to σ-conjugation, the longitudinal component (γL
e) turns out to be dominant. Its nonresonant dispersion relations are described by the coefficients of the power expansion formula, γL
e[(-ωσ; ωa, ω2, ω3) = γL
e(0; 0, 0, 0)[1 + AωL
2 + BωL
4 + CωL
6 + ⋯], where ωL
2 = ωσ
2 + ω1
2 + ω2
2 + ω3
2 and γL
e(0; 0, 0, 0) is the static limit value. In the infinite chain length limit, the CHF/6-31G static longitudinal electronic second hyperpolarizability per Si2H4 unit cell is estimated to attain 463 ± 10 × 103 a.u. whereas the A coefficient reaches 27.8 ± 0.9 a.u. The accuracy that could be reached from using this power expansion expression for estimating the second hyperpolarizability for other optical frequencies is discussed.
KW - Electronic second hyperpolarizability
KW - Frequency dispersion
KW - Polysilane
UR - http://www.scopus.com/inward/record.url?scp=3342970415&partnerID=8YFLogxK
M3 - Article
AN - SCOPUS:3342970415
SN - 0020-7608
VL - 70
SP - 737
EP - 743
JO - International Journal of Quantum Chemistry
JF - International Journal of Quantum Chemistry
IS - 4-5
ER -