title: New Evidence about the Spontaneous Symmetry Breaking: Action of an Asymmetric Weak Heat Source.
abstract: In the present study, we show how, in a stagnant water solution of uncharged aggregated achiral porphyrin-based molecules, a mirror-symmetry breaking (SB) can be induced and controlled by means of a weak asymmetric thermal gradient. In particular, it is shown that the optical activity of the aggregate porphyrin solution can be generated and reversed, in sign, only acting on the thermal ramp direction (heating or cooling). In order to avoid data misinterpretation, the aggregate structure modifications with the temperature change and the linear dichroism contribution to circular dichroism spectra were evaluated. A model simulation, using a finite element analysis approach describing the thermal flows, shows that small thermal gradients are able to give rise to asymmetric heat flow. The results reported here can be considered new evidence about the spontaneous symmetry breaking phenomenon induced by very weak forces having an important role in the natural chiral selective processes.
authors: Dipartimento di Scienze Chimiche and I.N.S.T.M. UdR of Catania, Università di Catania , Viale Andrea Doria 6, I-95125 Catania, Italy.|CNR-IPCF Istituto per i Processi Chimico-Fisici , Viale F. Stagno d'Alcontres 37, I-98158 Messina, Italy.
authors: Placido
authors: P
authors: Mineo
authors: CNR-IPCF Istituto per i Processi Chimico-Fisici , Viale F. Stagno d'Alcontres 37, I-98158 Messina, Italy.
authors: Valentina
authors: V
authors: Villari
authors: Dipartimento di Scienze Chimiche and I.N.S.T.M. UdR of Catania, Università di Catania , Viale Andrea Doria 6, I-95125 Catania, Italy.
authors: Emilio
authors: E
authors: Scamporrino
authors: CNR-IPCF Istituto per i Processi Chimico-Fisici , Viale F. Stagno d'Alcontres 37, I-98158 Messina, Italy.
authors: Norberto
authors: N
authors: Micali