Comparatively Large Second-Order Hyperpolarizability of Aromatic Sulfonate Anion with Short Cutoff Wavelength

Abstract
The second-order hyperpolarizabilities (β) of ionic species of sodium p-toluenesulfonate ( pTSNa) and its corresponding neutral derivative methyl p-toluenesulfonate ( p TSMe) in methanol were evaluated to be 2.2×10-29 and 1.2×10-29 esu, respectively, using the hyper Rayleigh scattering method at 1064 nm. Since ionic p TSNa has short cutoff wavelength of 280 nm as well as comparatively large |β| value, i.e., about twice that of neutral p TSMe and about two-thirds that of p-nitroaniline, aromatic sulfonate ions are concluded to be worth investigating as potential chromophores for second-order nonlinear optics.