Strong Enhancement of Nucleation Efficiency of Aqueous Ethylenediamine Sulfate Solutions by Nonphotochemical Laser-Induced Nucleation: Investigations on the Role of Solid Impurities in the Mechanism

The nonphotochemical laser-induced nucleation (NPLIN) phenomenon of an inorganic compound, ethylenediamine sulfate, exhibiting crystal chirality has been investigated. Strong enhancement of the nucleation efficiency upon laser irradiation is reported and is shown to rely on the presence of insoluble particles dispersed within the aqueous solutions since filtration drastically reduces the NPLIN effect. Elemental analyses (ICP-OES) show that these particles have a composition close to that of stainless steel. Then, we report a systematic study of the impact of doping the filtered solutions with several types of metallic particles on NPLIN efficiency as a function of irradiation wavelength and show that suitable doping permits to retrieve high nucleation probabilities. The impact of the geometry of light polarization on the distribution of crystal enantiomorphs is also investigated to assess the possibility of stereoselectively triggering the NPLIN effect in the case of ethylenediamine sulfate solutions irradiated with a single nanosecond laser pulse.