Introduction to Spectroscopy

Spectroscopy , What is spectroscopy, Interaction of radiation with matter,absorbtion,emission

[rviyengar]

An introduction to spectroscopy covers the interaction between light and matter, explaining concepts like wavelength, frequency, and the dual nature of light. It discusses absorption and emission spectra, Bohr's postulates on electron transitions, and Einstein's contributions to understanding light-matter interactions, emphasizing the importance of quantum mechanics in spectroscopy.


Highlights:
00:23 Spectroscopy is the study of the interaction between light and matter, which helps us understand various forms of spectroscopy. This course will cover fundamental principles and concepts of spectroscopy in detail.
-Light is an electromagnetic wave characterized by its wavelength and frequency, which are inversely proportional. Understanding these properties is crucial for comprehending spectroscopy's principles.
-The concept of a spectrum arises from dispersing light into its constituent wavelengths, leading to the formation of a spectrum. This process is the essence of spectroscopy.
-The historical background of spectroscopy traces back to the 17th century when Newton first described the solar spectrum. Later studies revealed dark lines in the spectrum, known as Fraunhofer lines.
06:50 The flame test is a simple yet effective spectroscopy experiment that reveals the emission spectra of different metal ions when heated. By analyzing emitted colors, we can identify specific elements present.
-Different metals produce distinct colors during the flame test, allowing for easy identification. Sodium shows yellow, while barium and lithium emit green and red respectively.
-The flame test illustrates the principles of emission and absorption spectroscopy. Sodium's emitted lines correspond to dark lines in the solar spectrum, known as the D lines.
-Light behaves as both a wave and a particle, a concept developed through historical experiments. This duality helps explain light interaction with matter and supports spectroscopy studies.
12:59 Light exhibits both wave and particle properties, known as wave-particle duality. This concept is essential for understanding phenomena like the photoelectric effect and quantum mechanics.
-The photoelectric effect demonstrates how light can cause electron emission, indicating its particle-like behavior. This phenomenon supports the need for a dual understanding of light.
-Compton's experiment showed a change in wavelength when X-rays collide with electrons, revealing energy shifts that further validate light's particle characteristics.
-Quantum mechanics emerged from the understanding of wave-particle duality, revolutionizing physics and providing insights into atomic structures and interactions.
19:40 Bohr's condition relates the energy difference between stationary states of matter to the frequency of light, described by the equation Ef - Ei = hν. While Bohr proposed this concept, Einstein later explained the mechanisms behind absorption and emission processes in quantum transitions.
-Einstein's postulation of light absorption rates being proportional to radiant energy density is crucial for understanding energy transitions in quantum mechanics. This was an extension of Bohr's initial ideas.
-The two types of transitions, absorption and emission, are fundamental in quantum mechanics, with absorption requiring light while spontaneous emission occurs without it. This distinction is essential for understanding atomic behavior.
-Einstein's absorption coefficient, B12, quantifies the rate of excitation from ground to excited states, illustrating how molecular populations shift in response to light. This mathematical formulation is vital for studying quantum transitions.
27:13 Einstein's coefficients for absorption, stimulated emission, and spontaneous emission are fundamental to understanding quantum mechanics. They indicate how light interacts with matter, influencing various physical processes.
-The relationship between Einstein's A and B coefficients demonstrates the connection between spontaneous and stimulated emission processes. This relationship is crucial for understanding light-matter interactions.
-Einstein's assumption that energy levels of atoms are quantized laid the groundwork for modern quantum mechanics. This assumption is vital for explaining various phenomena in physics and chemistry.
-The calculation of energy from photons illustrates practical applications of these coefficients in technology, such as LED lighting. Understanding energy calculations helps in optimizing energy-efficient devices.

[space-time-somdeep]

Such a beautiful letter.. thank you professor..

I'm student of Remote Sensing, Earth Observation.. it's really helpful sir

[shalinishalu]

Out of the world Sir...🪄✨.. Don't at all stop your work Sir, Then only students who are not blessed with tactful staffs can be beneficial Sir🙏💫

[jaydeepsahu]

best lecture i have seen so far in NPTEL

[gyankavetat]

Really it was very helpful. thank you sir for your time..

[malayablessingswhiteson]

This is fantastic, your work is much appreciated.

[gajananmohite]

Thank you Very easily introduce spectroscopy

[theoutlawdrive]

Thank you for the lecture sir, really good explanation.

[ahmedtaher]

Amasing explanation thank you from khartoum sudan

[feelgood]

Thank you sir, class is easily understandable

[seyahkaghaz.]

Great video.. Sir.. it's a bit problematic to find the sequence of video uploaded in the given topic..

[chunni_boy]

If we consider all of it as particles in wave form? I think that would be the right interpretation!

As long as those particles are not interested to interact with the out going slit

[ShashiSamdarshi]

You didn't mention bibilography on the introduction to spectroscopy. So you are requested to suggest.