Electron

Electron motion in atomic systems, which happens on timescales of attoseconds, is at the heart of all phenomena in nature (except for nuclear processes). Electron motion is responsible for the emission of light and photosynthesis in plants. Electron motion across biological molecules transports information in our nerves and is involved in processing this information in our brains. Moreover, the valence electrons are responsible for binding atoms to form molecules. The structural change of…

Critical assessment of the article: Quantitative analysis by Auger Electron Spectroscopy 1 Introduction When the outer electron fills the vacancy left by an ionized electron in the inner shell, the released energy can be passed to another outer electron that causes further emitting of an electron with characteristic energy, this is the basic principle of the Auger electron spectroscopy (AES) [1]. Nowadays, AES is almost an indispensable tool in nanoscience research for its high surface…

Reflection High-Energy Electron Refraction Intensity Oscillations Reflection high-energy electron refraction (RHEED) has been used as a surface probe for in situ observation of monolayer growth using molecular beam epitaxy (MBE) because of its high surface sensitivity and a near grazing incidence. It utilizes diffraction of electrons by surface atoms[1] and the RHEED intensity oscillation can convey morphological information of the growth surface if the intensity oscillation pattern is properly…

Transmission electron microscopy, or TEM, is a variation of low field, high-powered electron microscopy. Created by Ernest Ruska and Max Knoll of the Berlin Technische Hochschule in 1931, the invention of this novel microscope allowed for the surpassing of the visible light resolution barrier. Since its inception, the TEM has become a resolution standard in the field of imagery, and further advances have led to the progression of high quality atomic viewing. The development of the electron…

Electron Motion Control and Imaging M. Th. Hassan Electron motion in atomic systems, which happens on timescales of attoseconds (10-18s), is at the heart of all phenomena in nature. For instance, the motion of electrons in the chemical bonds determines the structure change in the molecules. Therefore, controlling this fast electron motion, in turn, allows to control the molecular structure change. Additionally, recording snapshots of the electron motion will provide real-time access to all…

Using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) images and spectra were obtained from various samples of silica and platinum on silica. Each sample contains unique structures which were prepared by etching the surface of silica in different conditions. A scanning electron microscope is a type of electron microscope that produces images of topography and composition by scanning a sample with a focused beam of electrons. Samples can be observed in high vacuum,…

Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) are two very widespread techniques for examining various properties of substances in many fields of study. These fields can range from biology to chemistry to geology and several others (5). Both work by using the electromagnetic properties of the ways that electrons travel and interact with other atoms. Because electrons have a shorter wavelength of motion and a much higher energy than light, electron microscopy has a…

scanning electron microscope (SEM) was invented by Manfred von Ardenne in 1937 (McMullan). However, further development of the SEM was accomplished by Charles Oatley and his colleagues at Cambridge University (McMullan; Egerton 17). He and his colleagues acquired their first images from the SEM in 1951 (Egerton 17). The SEM was developed because if a TEM is utilized, a specimen must be made extremely thin to prevent the electrons from dispersing inside the specimen and so the electrons are not…

last years, it has read that the electron transfers have relations with many processes, such us the photosynthesis (biology), organic synthesis (organic chemistry) or charge-transfer complexes (inorganic chemistry). It is important to know that most of the electron transfer occurs due to the metals, metals complexes and organometallic compounds. In this chapter a review of earlier electron donors and the different electron transfer will be developed. 1.1 Organic electron donors Since the earlier…

within the electric field is called voltage. The free electrons at the higher potential have more electrical potential energy whereas the free electrons at lower potential have less electrical potential energy. Voltage is measured in volts (V). Resistance: Resistance is the opposite force that resists the flow of electrons. The electrons that are moving freely through the conductor will collide continuously with the atoms. This causes the free electrons to lose their energy. Hence, the electric…