Quantum mechanics

fact that certain atomic nuclei exhibit magnetic property to determine their chemical and physical properties for various uses that we’ll discuss later. History of NMR Spectroscopy Year Individual Discovery 1921 Stern and Gerlach Basis of quantum theory is confirmed by carrying out atomic and molecular beam experiments 1925 Ulhenbeck & Goudsmith Discovered the concept of spinning electron to the magnetic dipole moment. 1938 Isidor Rabi Described Nuclear Magnetic Resonance in molecular…

Circular Dichroism (CD) fundamentals. CD is defined as the difference between absorptions of left (Al) and right (Ar) circularly polarized light beams, CD=Al-Ar For each absorption band, the CD of two enantiomers are always exactly opposite. Theory. For each electronic transition one can define an electric (µij≠0) and a magnetic (mij≠0) transition dipole. Both can lead to absorption of radiation, the intensity of which is directly related to the oscillator strength f, fij≈| µij |2+ | mij |2 In…

Gilbert Lewis first introduced his theoretical dot structures in 1916. Today, these same dot structures are used to illustrate the chemical bonding nature of atoms. How did Lewis formulate these brilliantly simple representations of nature? The Lewis Dot Structures we know today actually derive their functionality from Lewis’ own model of the atom, the Theory of the Cubical Atom. This essay will explore the functionality of Lewis’ cubical atom and how this model led to the Lewis Dot Structures.…

In 1959, metal–oxide–semiconductor field-effect transistor (MOSFET) was invented by Dawon Kahng and Martin M. (John) Atalla at Bell Labs. Julius Edgar Lilienfeld had already patented the basic principle of this kind of transistor in 1925. But later the Bell Labs edition was allocated the name bipolar junction transistor, or merely junction transistor, and design of Lilienfeld came to be identified as field effect transistor. Later, Jean Hoerni found that Silicon dioxide (SiO2) should be used to…

substrate. For example, when using two semiconductors with similar lattice constants, such as InAs and GaAs, a quantum well can be fabricated in roughly three stages. In the first stage, the Gallium and Arsenic chambers are opened for a calculated duration. The Ga and As particles…

Table of content Introduction Two dimensional electron system Hall geometry Classical interpretation of IQHE Quantum mechanical interpretation of IQHE Significance of IQHE References Introduction The integral quantum hall effect (IQHE) was first discovered by Klaus von Klitzing and coworkers in 1980. It was demonstrated by two dimensional electron system in a device called metal oxide semiconductor field effect transistor (MOSFET), under low temperature and large magnetic…

Eureka! Do you remember that pleasant feeling when a brilliant idea flashed into your head? Over 2000 years ago in ancient Greece, a physicist Archimedes was trying to solve a problem of physics. One day, while taking a bath, he suddenly got an inspiration, and discovered a breakthrough principle. He got so excited about this discovery that he leapt out the bathtub, ran through the streets without his clothes, and cried out, "Eureka!”: in English, “I’ve found it!”, the word to express our…

To facilitate an accurate description of the localized d and f electrons in the solids, the self interaction correction is introduced. Within the LSDA, the spurious self-interaction tends to underestimate their localization. In SIC-LDA formalism, the localized electrons see a potential (SIC potential) different from that of the delocalized ones for which the self-interaction vanishes and whose potential therefore reduces to that of the LSDA. It is known that self-interaction is important only…

Pangea! It was the supercontinent that existed about 300 million years ago. According to Alfred Wegener’s theory, long before us humans existed all of the continents used to be one large landmass. Who is Alfred Wegener you might ask? Alfred Wegener was a German polar researcher, geophysicist, and meteorologist born in Berlin on November 1, 1880. I chose to research about Alfred Wegener’s life and his struggles because we are currently focusing on the continental drift theory in science class. He…

Albert Einstein designed his own laws of nature. He changed the way we use to see light, gravity, and time. Most scientists in our day in age agree with what Albert Einstein has declared, but some scientists seemed to not understand what he was saying. Albert Einstein gave scientists the ability to know that atoms and molecules exist through Brownian motion. Albert was one who experimented the photoelectric effect in which he established that light has both a wave and a particle. Light particles…