polaron oscillations (IMAGE)
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Fig. 1. (a) Chemical structures of ethylene glycol (EG), isopropyl alcohol (IPA), and water (left), together with a sketch of an electron solvated in water (right). The electron (blue contour) attracts the hydrogen atoms of water molecules, thereby polarizing its environment and generating a self-consistent potential trap for the electron. The electron solvated this way represents an elementary quantum system. (b) The concerted motion of the electron and the cloud of polarized alcohol or water molecules represents an elementary excitation, a so-called polaron. The polaron is essentially an oscillatory motion of the spherical electric charge density around the electron as sketched in panels (+), (0), and (-). (c) Schematic spectra of the incoming THz pulse (red line) and the THz pulse transmitted through the excited sample (blue line). The polaron oscillations result in a periodic shift of the center frequency of the THz pulse, shown on the right-hand side as a function of time after electron generation. In the particular measurement, two electrons per 1 million alcohol molecules were present in ethylene glycol.
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MBI
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