Landsberg graduated from the Moscow State University in 1913, and then taught there from 1913–1915, 1923–45 and 1947–51. From 1934, he simultaneously worked also in the Physical Institute of the Academy of Sciences of the USSR. In 1951–57 he was Professor of the Moscow Institute of Physics and Technology. Landsberg conducted pioneering studies on vibrational scattering of light in crystals beginning in 1926. In 1928, Landsberg and Mandelstam discovered a phenomenon of combinatorial scattering of light. Landsberg discovered the fine structure in Rayleigh scattering. In 1931, he discovered a phenomenon of selective scattering of light. He laid the foundation to spectroscopy of organic molecules and to the studies on inter- and intra-molecular interactions in the gaseous, liquid and solid phases in the USSR. He founded a major school on atomic and molecular spectral analysis. He developed techniques for the spectral analysis of metals and alloys, and for the analysis of complex organic mixtures, including motor fuels. He is the author of the famous course of "Optics", and editor of the most popular "Elementary Textbook on Physics". In 1946 he became full member of the Soviet Academy of Sciences. He later founded the Commission on Spectroscopy at the Academy, which in 1968 was transformed into the Institute for Spectroscopy Russian Academy of Sciences. Landsberg was awarded two Orders of Lenin and several medals.
Discovery of the combinatorial scattering of light
Beginning from 1926, Mandelstam and Landsberg initiated experimental studies on vibrational scattering of light in crystals at the Moscow State University. Their intention was to prove the theoretical prediction made by Mandelstam in 1918 regarding the fine structure splitting in Rayleigh scattering due to light scattering on thermal acoustic waves. As a result of this research, Landsberg and Mandelstam discovered the effect of the inelastic combinatorial scattering of light on 21 February 1928. They presented this fundamental discovery for the first time at a colloquium on 27 April 1928. They published brief reports about this discovery in Russian and in German and then published a comprehensive paper in Zeitschrift für Physik. In the same year of 1928, two Indian scientists C. V. Raman and K. S. Krishnan were looking for "Compton component" of scattered light in liquids and vapors. They found the same combinatorial scattering of light. Raman stated that "The line spectrum of the new radiation was first seen on 28 February 1928." Thus, combinatorial scattering of light was discovered by Mandelstam and Landsberg a week earlier than by Raman and Krishnan. However, the phenomenon became known as the Raman effect because Raman published his results earlier than Landsberg and Mandelstam did. Nonetheless, in the Russian-language literature it is traditionally called "combinatorial scattering of light".
