{"id":293,"date":"2018-11-16T06:33:26","date_gmt":"2018-11-16T06:33:26","guid":{"rendered":"http:\/\/phyp10.epgpbooks.inflibnet.ac.in\/?post_type=chapter&p=293"},"modified":"2019-04-30T08:31:37","modified_gmt":"2019-04-30T08:31:37","slug":"raman-effect","status":"publish","type":"chapter","link":"https:\/\/ebooks.inflibnet.ac.in\/phyp10\/chapter\/raman-effect\/","title":{"rendered":"Raman Effect"},"content":{"raw":"
\"epgp<\/a>\r\n<\/span><\/div>\r\n
\r\n\r\n \r\n\r\nContents:<\/strong>\r\n\r\n \r\n\r\n1.\u00a0\u00a0\u00a0\u00a0 Introduction: A brief about Sir Chandrasekhar Venkata Raman\r\n\r\n2.\u00a0\u00a0\u00a0\u00a0 Raman Effect\r\n\r\n3.\u00a0\u00a0\u00a0\u00a0 How Raman Measures the Effect of Light Scattering?\r\n\r\n4.\u00a0\u00a0\u00a0\u00a0 Classical theory of Raman Effect\r\n\r\n5.\u00a0\u00a0\u00a0\u00a0 Limitations of the Classical Theory\r\n\r\n6.\u00a0\u00a0\u00a0\u00a0 Quantum theory of Raman Scattering\r\n\r\n7.\u00a0\u00a0\u00a0\u00a0 Why the Stokes lines are higher in intensity than the Anti- Stokes lines?\r\n\r\n8.\u00a0\u00a0\u00a0\u00a0 Setup used for Raman Effect\r\n\r\n \r\n\r\nSummary<\/strong>\r\n\r\n \r\n

The students will be able to learn about the Raman Effect and its classical and quantum theory. Also to understand the instrumentation for Raman spectroscopy.<\/p>\r\n\r\n<\/div>\r\n \r\n\r\n1. Introduction: A brief about Sir Chandrasekhar Venkata Raman<\/strong>\r\n\r\n \r\n

Chandrasekhar was born in 1888 in a village in southern India. As a child, Raman was precocious, curious and highly intelligent. His father was a college lecturer in mathematics, physics and physical geography, so the young Raman had immediate access to a wealth of scientific volumes. By the age of 13, he had read Helmholtz\u2019s Popular Lectures on Scientific Subjects.<\/span><\/p>\r\n \r\n

Raman was deeply interested in music and acoustics. While in college, he read the scientific papers of Lord Rayleigh and his treatise on sound as well as the English translation of Helmholtz\u2019s The Sensations of Tone. This initiated Raman\u2019s later interest in the physics of drums and stringed instruments such as the violin. He used fine-chalk powder and photography to investigate the vibrational nodes of drums; the white chalk remained only at the nodes of the vibrating membrane.<\/span><\/p>\r\n \r\n

2. Raman Effect<\/strong><\/p>\r\n \r\n

The phenomenon is named after the great Indian Physicist Sir Chandrasekhar Venkata Raman, who first published observations of the effect in 1928.<\/span><\/p>\r\n \r\n

When a parallel beam of monochromatic light goes through a gas or liquid or transparent solid, a part of light is scattered in all directions (It may be reflected, absorbed or scattered in same manner). The intensity of scattered light is inversely proportional to the fourth power of wavelength. It is found that the scattered light contains exactly the same wavelength as the incident light. This scattering is called as Rayleigh scattering (Elastic Scattering). Apart from this wavelength, the scattered light also contains some weak additional lines. As\u00a0<\/span>said earlier that this phenomenon was first discovered by Raman and his collaborators and is known as Raman Effect. A comparison of the wave numbers of these additional lines shows that these Raman lines are independent of the wavelength of the incident light but depends on the nature of scattering substance. For different scattering substance, the displacements of the Raman lines from the incident light are different. Thus, the displacements are characteristics of the scattering substance<\/span><\/p>\r\n\r\n

\r\n\r\n \r\n\r\nRemarks:<\/strong>\r\n\r\n \r\n