Esr dating ppt

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The interaction between an unpaired electron an nuclei with non zero nuclear spin is called the hyperfine interaction .

This leads to splitting of the ESR line and is known as hyperfine spectrum ESR spectrometer We need four essential components to build an ESR spectrometer: A monochromatic microwave source A waveguide for guiding the microwave power to the sample A cavity designed to ensure a proper coupling between the sample and the incoming wave.

1-2 GHz (L-band) and 2-4 GHz (S-band), 8-10 GHZ (X-Band), 35 Ghz (Q-band) and 95 GHz (W-band).

The most commonly used EPR spectrometer is in the range of 9-10 GHz (X-band).

Tuning of the frequency is achieved by slowly turning the screw on the top of the metallic case of the oscillator.

The frequency can be read out with the frequency counter located next to the source.

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Introduction Electron paramagnetic resonance (EPR), also known as electron spin resonance (ESR), is a sophisticated spectroscopic technique that detects free radicals in chemical and biological systems. Molecule that carry angular momentum of electronic origin. Molecule with paired electrons and zero magnetic field Diamagnetic Molecules with unpaired electrons and magnetic moment-Basic Principle Of ESR……………

Continous wave method: the sample is irradiated continuously with microwave radiation of fixed frequency while the magnetic field is slowly swept and the microwave absorption is measured for each field position Pulse EPR: short pulse of high microwave radiation are sent to the sample and the response in the absence radiation are recorded.

Measuring a CW-EPR spectroscopy can be influenced by various parameters, both instrumental and experimental.

A detector for microwave power to detect the response of the sample to microwave irradiation.

Microwave parts A gun oscillator is a monochromatic source of microwave.

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