Past colloquia and seminars


Variance analysis of dynamic light scattering data

Academic or specialist Seminar

We propose a novel method alternative to the classical Dynamic Light Scattering (DLS) technique for performing particle sizing on diluted dispersions of nanosized particles. Differently from DLS, which works by determining the correlation function of the intensity scattered by the sample, our method does not require the use of a correlator because it exploits the behavior of the variance (VAR) of the scattered signal as a function of the sampling time Δt. By using a wide range of sampling times Δtmin ≪ τc ≪ Δtmax, it is possible to recover the correlation time τc of the scattered field and, in turn (by using the Stokes–Einstein relation), the hydrodynamic diameter of the particles. The new method is endowed with an analytical expression for the error bars associated with to the VAR data. Extensive computer simulations carried out on monodisperse and narrow polydisperse samples show that VAR and DLS techniques provide fairly similar performances. The same results were obtained on calibrated polystyrene spheres and fluorescent perovskite nanoparticles tested with different setups and detection schemes.

When? 30.11.2023 11:15
Where? PER 08 0.58.5
Chemin du Musée 3
1700 Fribourg
speaker Prof. Fabio Ferri
Dipartimento di Scienza e Alta Tecnologia and To.Sca.Lab,
Università degli Studi dell’Insubria
Contact Département de Physique
Prof. F. Scheffold
Chemin du Musée 3
1700 Fribourg