Circular Dichroism (CD) fundamentals.
CD is defined as the difference between absorptions of left (Al) and right (Ar) circularly polarized light beams,
For each absorption band, the CD of two enantiomers are always exactly opposite.
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
Physics: Analogy of Light and Sound
Light and sound share many common aspects. Today, we will study some of notable similarities and differences between the two.
We can perceive both light and sound. We see through eyes and hear through ears. Both light and sound are waves. Light is an electromagnetic wave whereas sound is a mechanical wave. Light is created by interaction of electric and magnetic field. It does not require any medium for propagation, so it can propagate in free space. On the…
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…
Research question: To what extent is the maths behind the double pendulum correct and what are its limitations due to chaos theory.
Chaos theory is the idea, in simple terms, that certain natural events and occurrences are unpredictable in their behaviour. Examples of this are: weather, turbulent flow in certain liquids and even the double pendulum. These things can be explored and determined mathematically just how unpredictable they are and under what conditions they may become predictable,…
We now use the method described in Section 2 to studythe effects of electron-phonon interaction on the electronic transport properties of (C60-1X1)2(X=N,B) molecule. We set
tC-C=2.5 eV, αC-C=6.31 eV/Å, KC-C=49.7 eV/Å2  tC-B=1.17 eV, αC-B=6.04 eV/Å, KC-B=51.1 eV/Å2,tC-N=1.05 eV, αC-N=6.13 eV/Å, and KC-N=49.6 eV/Å2  and T=300 K in the calculations. The doped atoms are located at about the same distance from each lead and they are indicated with a different color from C atoms in each…
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…
Table of content
Two dimensional electron system
Classical interpretation of IQHE
Quantum mechanical interpretation of IQHE
Significance of IQHE
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…
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…
The Atomic Theory
The atomic theory serves as the basic foundation for the study of matter; it is of major importance to the study of Chemistry. The atomic theory has an interesting and lengthy history that shall be discussed. Furthermore, it has been perfected and discussed by many chemists over a number of years; all of their brilliant minds put together into one. There have been drastic changes to the atomic structure in modern times, proving we still do not know everything. Technology…
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…