ОписаниеAEC-71-9066 THE ATOM IS "SEEN"… Scientists can now see a single atom within a molecular structure through a technique developed, at the University of Chicago. Attempts to render single atoms visible have been one of the major goals of the development of the electron microscope. A transmission scanning electron microscope, designed and built at the University, was used to photograph pairs of single uranium atoms (A) and chains of thorium atoms that were chemically incorporated into molecules consisting of carbon, hydrogen, and oxygen atoms. Deposits of these molecules on a thin carbon film were positioned in the microscope, and a beam of electrons was scanned across the specimen. Electrons scattered from the specimen structure as the beam passed through it were detected and used to generate an Image on an oscilloscope — an instrument that converts electrical signals into pictures, much like a television screen. By properly combining the signals corresponding to electrons scattered with and without energy loss, the heavy atoms are made to appear as bright spots on a dark background. In this experiment two uranium atoms were placed at the ends of a large organic molecule formed by reacting urenyl acetate with 1,2,4, 5-benzene tetracarboxylic acid with the resulting image on the oscilloscope consisting of pairs of dots (A) corresponding to pairs of uranium atoms. Credit : Chicago University
Photo - Positive
![[ru-RU]Print](/Search6/Content/Images/pdf.svg){kind=small}
