Q1. Answer any five of the following questions in brief:
- (a)) Explain the origin of atomic spectrum. (150 words)
- (b)) What is meant by anisotropy of chemical bond? Give an example. (150 words)
- (c)) What makes TMS a molecule of choice to act as a reference in the NMR spectrometry? (150 words)
- (d)) What is meant by polarizability of a molecule? (150 words)
- (e)) In what way is NMR spectrometry different from other molecular spectroscopic methods? (150 words)
- (f)) What is the importance of 13C-NMR spectroscopy in structure determination? (150 words)
- (g)) What is the requirement of the vibrational mode of a molecule to be Raman active? (150 words)
- (h)) What is the photoelectric effect? Write the equation of Einstein's photoelectric law. (150 words)
Key Points:
- Atomic spectrum originates from electron transitions between discrete energy levels.
- Chemical bond anisotropy refers to directional variation in magnetic shielding, e.g., benzene's π-system.
- TMS is an ideal NMR reference: inert, volatile, shielded, giving a single signal at 0 ppm.
- Polarizability is the ease of electron cloud distortion by an external electric field.
Answer: The following provides a comprehensive answer to all eight sub-questions, adhering to the specified word limits and formatting guidelines from the MCH-020 Atomic and Molecular Spectroscopy course. Each sub-question addresses a fundamental concept in spectroscopy or quantum chemistry, ranging from the origin of atomic spectra and the properties of chemical bonds to specialized spectroscopic techniques like NMR and Raman, and the foundational photoelectric effect. The answers emphasize core princi...