A non-equilibrium quasistationary state in an ionic liquid caused by a focused laser

A radial pattern of polarization is observed in a Fe-based (but not in a Ga-based) room-temperature ionic liquid (RTIL) on irradiation by a focused laser. On switching the laser off, the pattern shows a fast (<1 s) change followed by a quasistationary structure for more than 100 s with decay exponents varying approximately from −0.2 to −0.02. Optical spectra of the RTILs indicate a band at 532 nm for the Fe-based RTIL and absence of this band in the Ga-based RTIL. A preliminary qualitative explanation based on the Hamiltonian Mean Field model of coupled rotators, where the rotators are charge transfer complex (CTC) dipoles created resonantly by the laser for the Fe-based RTIL, has been proposed.