Effect of the dynamical disorder on the second-order nonlinear optical responses of helicity-encoded polymer strands.
By combining classical samplings with quantum chemistry semiempirical time-dependent Hartree-Fock calculations, the high impact of dynamic fluctuations on the NLO properties of helical strands has been evidenced. In particular, these fluctuations are responsible for relative variations of approximately 20% in the hyper-Rayleigh responses in both pyridine-pyrimidine (py-pym) and hydrazone-pyrimidine (hy-pym) strands. Then, dynamical disorder has an even more important impact on the electric-field-induced second harmonic generation responses, whose variations can reach 2 (py-pym) or 5 (hy-pym) times their mean value. This work also highlights the relationships between the unit cell nature and helical conformation of foldamers and their second-order NLO responses. In particular, the octupolar symmetry of the hyper-Rayleigh depolarization ratios is related to the helix periodicity of three unit cells per turn in both compounds.
Méreau
Raphaël
R
Castet
Frédéric
F
Botek
Edith
E
Champagne
Benoît
B
D006835:Hydrazones / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D017711:Nonlinear Dynamics; D011108:Polymers / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry; D011743:Pyrimidines / Q000737:chemistry; D011789:Quantum Theory; D013816:Thermodynamics; D013997:Time Factors
D006835:Hydrazones; D011108:Polymers; D011725:Pyridines; D011743:Pyrimidines; C030986:pyrimidine; C023666:pyridine