Sulabha K. Kulkarni - Nanotechnology: Principles and Practices

Nanotechnology: Principles and Practices — read online for free the complete book (whole text) full work

Below is the text of the book, divided by pages. System saving the place of the last page read, allows you to conveniently read the book "Nanotechnology: Principles and Practices" online for free, without having to search again every time where you left off. Put a bookmark, and you can go to the page where you finished reading at any time.

Light

Font size:

↓

↑

Georgia Tahoma Arial Verdana

Reset

Interval:

↓

↑

Bookmark:

Make

1234567...101

Capital Publishing Company 2015

Sulabha K. Kulkarni Nanotechnology: Principles and Practices 10.1007/978-3-319-09171-6_1

1. Introduction to Quantum Mechanics

Sulabha K. Kulkarni 1

(1)

Physics Department, Indian Institute of Science Education and Research, Pune, India

1.1 Introduction

In Nanotechnology we are concerned with natural and synthetic materials in the size range of 1100 nm. At such a small size, very familiar classical, Newtonian mechanics or thermodynamics are not able to explain the observed properties of materials. We have to use quantum mechanics sometimes directly and sometimes through subjects like solid state physics or chemistry which use it to explain the properties and phenomenon of different materials. Those of you who are familiar with quantum mechanics and solid state physics can skip this and the next chapter and directly go to the third chapter. For those who would like to start new, let us discuss first the need of quantum mechanics and how it got developed so that it can be used to understand atoms, molecules, solids and nanomaterials. Box gives some historical milestones, which have led to quantum mechanics.

Box 1.1: Historical Milestones in the Development of Quantum Mechanics

Pre-quantum Era

• In 1669, Newton proposed that light had corpuscular or particle nature.
• Huygen claimed in 1690 that light had a wave nature.
• Kirchoff and others studied black body radiation around 1860.
• Maxwell proposed (1873) theory of electromagnetic waves.
• In 180304 Young performed double slit experiment, which showed that light had a wave nature.
• In 1887, Heinrich Hertz produced and detected electromagnetic radiation.

Old Quantum Theory Period

• In 1901, Max Planck showed that energy distribution in black body radiation could be explained properly only if one considered that the radiation was quantized or had a particle nature.
• In 1905, Einstein proposed a theory of photoelectric effect which decisively proved that quantum or particle nature was associated with electromagnetic waves.
• Compton effect (1920) could be explained only when particle nature of electromagnetic radiation was considered, supporting Max Plancks and Einsteins theories. Particles of electromagnetic waves were identified as photons.
• De Broglie (1923) argued that if electromagnetic waves were particles (photons) then why not particles have waves associated with them?
• Bohrs atom model (1913) with stationary states (why electrons should have some fixed energies) could be explained with de Broglie hypothesis.

Modern Quantum Theory Begins

• Heisenberg introduced (1925) Matrix Mechanics.
• Schrdinger equation (1926) gave the firm foundation for de Broglie hypothesis and later explained the electronic structure of atoms, molecules and solids.
• Davisson and Germer showed in 1927 that electrons can be diffracted. Regularly spaced atoms constitute multi-slit analogue of Youngs double slit experiment.
• Heisenberg proposed uncertainty principle in 1928.

This marks the beginning of Quantum Mechanics as it is practiced now!

In Kirchoffs time many scientists were interested in understanding the black body radiation (Box . The black body spectrum spreads over a large range of wavelengths and has a maximum in the intensity. Experiments on black body radiation led Stefan (1879) and Boltzman (1884) to establish Stefan-Boltzman law. According to this law, the total radiation from a black body is proportional to the fourth power of absolute temperature. If E is the intensity of total radiation, and T the absolute temperature,

(1.1)

where is known as Stefans constant. Its value is =5.669108 W/m2.

Fig. 1.1

Spectra of Black body radiation. Note that as the temperature increases, the spectral intensity increases and maximum intensity shifts to shorter wavelength. T 1, T 2 and T 3 are different temperatures in the increasing order

Box 1.2: Sir Isaac Newton (16431727)

Isaac Newton was born on 4th January 1643 in Woolsthrope, Lincolnshire, England. His father was a farmer who died two months before Isaac was born. His mother remarried and Newton had a difficult childhood. He graduated from Trinity College, Cambridge and studied Philosophy of Descartes, Gassendi, Hobbs and Boyle. He somewhere wrote, Plato is my friend, Aristotle is my friend, but my best friend is truth. He also studied Keplers optics and had a keen interest in mathematics. In 1665, he had to return home from college when an epidemic of plague broke.

In a period of 2 years at home, he did some revolutionary work in mathematics, physics and astronomy. He then laid the foundations of differential and integral calculus. He returned to college in 1667 and by 1669 he became well known due to his achievements in mathematics. In 1669, just at the age of 27, he was appointed as a Professor, Lucasian chair in Cambridge. His first lectures as a Professor were on Optics. All had believed since the time of Aristotle that white light was just a single component of radiation. But Newtons work during 2 years at home during plague, made him think otherwise. Newton became the Fellow of Royal Society in 1672. He left Cambridge and took a Government position as a Warden of Royal Mint in 1696 and Master in 1699. Newton took his job very seriously and contributed a lot to the work of Mint. Officially he left his Cambridge position in 1701. Newton was a real genius and worked in almost all areas important at that time but he is best known for his work in

• Laws of Gravity
• Optics and
• Co-foundation of Calculus

His famous books are

• Philosophiae Naturalis Principa Mathematica (1687) and Opticks (1704).
• Philosophiae Naturalis Principa Mathematica, which is often referred to just as Principa, is considered to be one of the best scientific document ever written.

Newton was elected in 1703 as a President of Royal Society and remained so getting elected every year until his death on 31st March 1727 in London, England.

Box 1.3: Black Body Radiation

All materials absorb and emit energy. The intensity of energy radiated and absorbed by a body are equal if the object is in thermal equilibrium with its surrounding. However if the body is above the temperature of its surrounding then it emits radiation, which is known as black body radiation. Black body is thus an object that can absorb all radiation incident on it (no reflection or transmission!) or emits all radiation when above the temperature of the surrounding. Typical black body spectra are illustrated in Fig..

Total intensity of radiation (area under the curve) and intensities at different emission wavelengths of a perfect black body irrespective of its material depend on the temperature. In practice a cavity with a small hole can act like a black body.

Next page

1234567...101

Light

Font size:

↓

↑

Georgia Tahoma Arial Verdana

Reset

Interval:

↓

↑

Bookmark:

Make

Similar books «Nanotechnology: Principles and Practices»

Look at similar books to Nanotechnology: Principles and Practices. We have selected literature similar in name and meaning in the hope of providing readers with more options to find new, interesting, not yet read works.

Supriya Kulkarni

Breast Imaging Essentials : Case Based Review

Rakesh K. Sindhu

Nanotechnology: Principles and Applications

J. Storrs Hall

Nanofuture: Whats Next For Nanotechnology

Lorna Brazell

Nanotechnology law : best practices

Kulkarni

The Art Of Songwriting: How To Write Your Own Complete Song In 60 Minutes Or Less

Kulkarni Kunal

Oxford Handbook of Key Clinical Evidence

Bai Jamuna Aswathanarayn

Nanotechnology Applications in the Food Industry

Chaudhery Mustansar Hussain

Nanotechnology in Environmental Science, 2 Volumes

Kulkarni

Java EE 8 development with Eclipse

Jeremy Ramsden

Nanotechnology: An Introduction

C. Binns

Introduction to Nanoscience and Nanotechnology

Michael T. Burke

Nanotechnology: The Business (Perspectives in Nanotechnology)

Discussion, reviews of the book Nanotechnology: Principles and Practices and just readers' own opinions. Leave your comments, write what you think about the work, its meaning or the main characters. Specify what exactly you liked and what you didn't like, and why you think so.