Introduction to Quantum Mechanics 1

Thermal Radiation and Experimental Facts of the Quantization of Matter

Ibrahima Sakho

• Publisher: Wiley-ISTE
• Year: 2019
• Print ISBN: 9781786304872
• eBook ISBN: 9781119671442
• Edition: 1
• Topic: Physical Sciences
• Subtopic: Thermodynamics

The conception of lasers and optoelectronic devices such as solar cells have been made possible, thanks to the modern day mastery of processes that harness the interaction of electromagnetic radiation with matter. This first volume is dedicated to thermal radiation and experimental facts that reveal the quantification of matter. The study of black body radiation allows the introduction of fundamental precepts such as Plancks law and the energy-related qualities that characterize radiation. The properties of light and wave–particle duality are also examined, based on the interpretation of light interferences, the photoelectric effect and the Compton effect. This book goes on to investigate the hydrogen atomic emission spectrum and how it dovetails into our understanding of quantum numbers to describe the energy, angular momentum, magnetic moment and spin of an electron. A look at the spectroscopic notation of the states explains the different wavelengths measured from the splitting of spectral lines. Finally, this first volume is completed by the study of de Broglies wave theory and Heisenbergs uncertainty principle, which facilitated the advancement of quantum mechanics.

1
Thermal Radiation

General objective

Gain knowledge on energy-related quantities and the laws of thermal radiation.

Specific objectives

On completing this chapter, the reader should be able to:

• – define thermal radiation;
• – know the origin of thermal radiation;
• – know the relations between energy, photon wavelength and frequency;
• – distinguish between black body and gray body;
• – define the energy-related quantities (flux, exitance, radiance and intensity);
• – apply the law of conservation of radiant flux;
• – state Lambert’s, Kirchhoff’s, Stefan-Boltzmann and Wien’s laws;
• – provide an interpretation of Planck’s law;
• – apply the laws of thermal radiation;
• – find the useful spectrum from a given isotherm of the black body.

Prerequisites

• – structure of matter;
• – modes of energy transfer;
• – range of electromagnetic waves.

1.1. Radiation

1.1.1. Definition

An object at temperature T can emit or absorb light waves of several frequencies [PÉR 86, PER 11, SAK 12]. The distribution of the energy exchanged by the object with its external environment depends on the temperature T. When two objects at different temperatures are in contact, thermal energy (heat) is transferred from the hot object to the cold object. By contrast, radiation is energy that is carried by an electromagnetic wave. In this case, energy is transferred by emission and absorption of light waves. Hence, by definition, thermal radiation is the electromagnetic radiation emitted by any object at non-zero temperature T.

1.1.2. Origin of radiation

In 1900, Max Planck laid the foundations of quantum physics by studying the black body emission s...

Table of contents

• Cover
• Table of Contents
• Foreword
• Preface
• 1 Thermal Radiation
• 2 Wave and Particle Aspects of Light
• 3 Quantum Numbers of the Electron
• 4 Matter Waves – Uncertainty Relations
• Appendices
• References
• Index
• End User License Agreement