The movement of individual electrons in a molecule can be controlled



    Physicists for the first time were able to track the movement of individual electrons in a molecule and showed that these processes can be controlled. In the future, this will make it possible to control the course of chemical reactions and biological processes in order to obtain the desired result from several possible reaction variants of the same chemicals.

    The results of a study conducted at the Swiss Higher Technical School in Zurich with the participation of Oleg Tolstikhin, doctor of physical and mathematical sciences of the Moscow Institute of Physics and Technology, as well as theoreticians from Denmark, Belgium and Canada, were published on October 22, 2015 in the journal Science.

    It is reported that the motion of electrons is controlled using ultrashort laser pulses with a wavelength of 800 and 1300 nanometers. Electron displacements were observed in the spectrum of high harmonics arising from the interaction of a laser pulse with a molecule.



    Using attophysical methods, researchers tracked the restructuring of the electronic shell. This is a key process in understanding the chemical reaction, since the redistribution of electrons corresponds to the formation of new chemical bonds.

    A group led by Hans Jacob Werner of the Swiss Higher Technical School in Zurich previously conducted a series of experiments that convincingly demonstrate the possibility of such observations, but now the researchers have taken the last step: they de facto tracked the movement of electrons with a resolution of 100 attoseconds (1 attosecond = 10 -18  seconds) and showed how to control electrons.

    During the experiment, electrons moved along the linear iodoacetylene molecule (HCCI), which are elongated chains of four atoms - hydrogen, two carbon atoms and an iodine atom. Under the influence of laser pulses, the configuration of the electron shell changed: a vacant place for an electron appeared in it. Under the action of the laser, a superposition of two quantum states of this “hole” arose: it can be detected with some probability at once at both ends of the molecule.



    “We can control the movement of electrons in the molecule, which means that if this technology is developed, we can control the outcome of chemical reactions. For example, in a mixture of gases where a chemical reaction can take place, its outcome may be one, or may be different. By shining with a “right” laser with a “correct” pulse shape, one of the outcomes can be dominant, ” explained Oleg Tolstikhin, doctor of physical and mathematical sciences, co-author of scientific work.

    According to Oleg Tolstikhin, scientific work can find application, in particular, in the development of new medicines: “If you can control the outcome of a chemical reaction, you can create substances, large molecules — any medicine is a large molecule — which can usually be obtained as a result of chemical reactions in negligible amounts, and it will be possible, for example, to get the right substance in half the cases, ”he said.

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