It is shown that the pump-probe spectroscopy of Λ-type system for the D2 transition of 87Rb exhibits additional absorption enhancement peaks due to velocity selective optical pumping along with the electromagnetically induced transparency (EIT). The separation of these peaks is consistent with the hyperfine splitting of the upper levels. For 85Rb the peaks are not clearly discernible since the hyperfine splitting is much smaller.

Flavonol 4'-chloro,3-hydroxyflavone (Cl-3HF) has been investigated in solvents of varying polarity and hydrogen-bonding capacity as well as in aqueous micelle solutions. Quantum chemical calculations indicate that although the Cl-atom at the 4'-position of the 2-phenyl ring weakly perturbs the electron distribution of the parent 3-hydroxyflavone, the nuclear framework remains largely intact, and excited state intra-molecular proton-transfer (ESIPT) is feasible. The ESIPT process in both polar solvents and micelles was found to be fast and irreversible, with remarkably long time-constants of several tens of picoseconds. This dramatic inhibition of the ESIPT rate (which is intrinsically a sub-picosecond event) could be rationalized in terms of the emergence of complexes between the solvent and the enol form of Cl-3HF, whose dynamics is coupled to the relatively slow dynamics of inter-molecular hydrogen bonds. In the micelle solutions, spectroscopic data establish that the guest Cl-3HF molecules localized almost exclusively at the polar exterior shell, where they experienced a nearly uniform local environment similar to that in moderately polar solvents. Thus, the Cl-3HF molecules tend to avoid the non-polar core of the micelles, in spite of being strongly hydrophobic themselves. This apparently unusual observation is explained by the formation of inter-molecularly hydrogen-bonded complexes between the guest Cl-3HF and the water molecules tethered to the polar shells of the micelles.

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In this article, we report the generation of alternating current by the application of constant and ramping DC voltages across oil–water interfaces. The work reported here can be broadly divided into two parts depending on the shapes of oil–water interfaces, i.e., flattened and curved. In the first part, an alternating current of ∼100 nA (amplitude) was generated by applying a constant DC voltage of −3 V and above across a freestanding and flattened oil–water interface. In another part, an alternating current of ∼150 nA (amplitude) was generated by applying a ramping up DC voltage starting from −5 V to 5 V, then again ramping back down to −5 V for the freestanding and curved interface. The suggested qualitative mechanism that engenders such a phenomenon includes the oil–water interface acting like a membrane. This membrane oscillates due to the electrophoretic movement of ions present in the aqueous phase by the application of a DC voltage across the interface. This electrophoretic movement of ions across oil–water interfaces causes Faraday instabilities leading to oscillations of the said interface. This method could also be used to study the stress levels in the interfacial films between two immiscible liquids. It explores the more-than-Moore’s paradigm by finding a substitute to a conventional alternator/inverter that generates alternating current upon applying a DC voltage input. This work would be of substantial interest to researchers exploring alternatives to conventional AC generators that can be used in liquid environments and in the design of novel integrated circuits that could be used for unconventional computing applications.