IR Spectroscopy Handwritten Notes
Download free handwritten notes on IR Spectroscopy covering topics like fundamental modes of vibrations, sample handling, factors affecting vibrations, instrumentation, detectors, and applications.
Keywords:
- IR Spectroscopy PDF notes
- Instrumental Methods of Analysis notes
- BPharmacy Semester 7 handwritten notes
- Fundamental modes of vibrations
- Golay Cell, Bolometer, Thermocouple
- Applications of IR Spectroscopy
IR Spectroscopy: A Comprehensive Guide
Infrared (IR) spectroscopy is a powerful analytical technique used to study the vibrational transitions in molecules. It provides valuable information about the functional groups present in a compound, making it indispensable in fields like pharmaceuticals, chemistry, and material science. Below is a detailed explanation of the key concepts covered in these handwritten notes.
1. Introduction to IR Spectroscopy
IR spectroscopy involves the interaction of infrared radiation with matter. When molecules absorb IR radiation, they undergo vibrational transitions, which correspond to specific energy levels. These transitions provide insights into the molecular structure and chemical bonds present in the sample.
2. Fundamental Modes of Vibrations
Polyatomic molecules exhibit different types of vibrational modes:
- Stretching Vibrations: Involve changes in bond length without altering bond angles. These can be symmetric or asymmetric.
- Bending Vibrations: Involve changes in bond angles without altering bond lengths. Types include scissoring, rocking, wagging, and twisting.
3. Sample Handling
Proper sample preparation is crucial for accurate IR analysis:
- Solid samples are often mixed with potassium bromide (KBr) and pressed into pellets.
- Liquid samples are placed between two salt plates (e.g., NaCl or KBr).
- Gaseous samples are analyzed in gas cells with IR-transparent windows.
4. Factors Affecting Vibrations
Several factors influence the vibrational frequencies observed in IR spectra:
- Molecular Mass: Heavier atoms result in lower vibrational frequencies.
- Bond Strength: Stronger bonds vibrate at higher frequencies.
- Hydrogen Bonding: Can cause broadening of peaks due to intermolecular interactions.
5. Instrumentation
A typical IR spectrometer consists of the following components:
- Source of Radiation: Nernst glower, globar, or incandescent wire for generating IR radiation.
- Wavelength Selector: Monochromators or interferometers to isolate specific wavelengths.
- Detectors: Common detectors include Golay Cell, Bolometer, Thermocouple, Thermister, and Pyroelectric detectors.
6. Applications
IR spectroscopy has diverse applications across various fields:
- Functional Group Identification: Used to identify functional groups like alcohols, carbonyls, and amines based on characteristic absorption bands.
- Drug Analysis: Helps in determining the purity and composition of pharmaceutical compounds.
- Environmental Monitoring: Detects pollutants and greenhouse gases in the atmosphere.
- Material Science: Analyzes polymers, coatings, and other materials for quality control.
These handwritten notes provide a comprehensive overview of IR spectroscopy, making them ideal for BPharmacy Semester 7 students studying Instrumental Methods of Analysis.
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