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Carbon-12 Stable
Carbon-12 Stable

KEY Midterm Exam 1 Sept.14, 1999 Chemistry 211 PAGE 1 0f 5
KEY Midterm Exam 1 Sept.14, 1999 Chemistry 211 PAGE 1 0f 5

... (a) atoms with different numbers of protons and neutrons. (b) atoms with the same number of neutrons and electrons. (c) atoms with the same atomic number and different mass numbers. (d) atoms with the same mass number but different atomic numbers. ...
Electron-Cloud Energy and Angular Distributions
Electron-Cloud Energy and Angular Distributions

Basic Chemistry Lecture Notes - Roderick Biology
Basic Chemistry Lecture Notes - Roderick Biology

Molecular Spectroscopy
Molecular Spectroscopy

HIGHER TIER CHEMISTRY MINI-MOCK UNIT 2
HIGHER TIER CHEMISTRY MINI-MOCK UNIT 2

Lecture Notes3 - Haldia Institute of Technology
Lecture Notes3 - Haldia Institute of Technology

... In 1927 C. J. Davisson and L. H. Germer of the Bell Telephone Laboratory, USA performed an experiment on the diffraction of electrons from the surface of a solid crystal. The apparatus designed and built by them consisted of a vacuum chamber in which electrons were produced from a heated tungsten fi ...
PIB and HH - Unit 4 - Chemical Names and Formulas
PIB and HH - Unit 4 - Chemical Names and Formulas

...  Ionization energy increases as you move from left to right in a given period.  Atomic radii increase within a given group because the outer electrons are farther from the nucleus as you go down the group.  Ionization energy decreases as you move down through a group. ...
Document
Document

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Document

29.2 Chemical Bonds
29.2 Chemical Bonds

...  When substances are dissolved in water they divide into two categories called acids and bases.  An acid creates a sour taste and can dissolve reactive metals like zinc. Vinegar and lemon juice are examples of acids.  A base creates a bitter taste and tends to feel slippery. Ammonia is an example ...
Compounds Power point
Compounds Power point

Far-infrared „ 88 m… electroluminescence in a quantum cascade
Far-infrared „ 88 m… electroluminescence in a quantum cascade

(TEQ) Model of the Electron - Superluminal quantum models of the
(TEQ) Model of the Electron - Superluminal quantum models of the

... frequency and a wavelength, and carrying energy and momentum. • can easily pass through the speed of light (being massless). • can generate a photon or an electron depending on whether the energy quantum’s helical trajectory is open or closed. ...
Environmental Effects on Atomic Energy Levels.
Environmental Effects on Atomic Energy Levels.

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The Periodic Table of Elements and Atoms…

... chart or table called the Periodic Table of Elements. Today’s periodic table of elements based on Mendeleev’s version groups the elements by similar properties. It gives the symbol, the atomic number, and the atomic mass of ...
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Single-electron tunneling in the fractional quantum Hall effect regime∗

... by a reduced charge e∗ . This reduced charge is recognized as the fractional charge of the quasiparticle excitations in the p/(2kp + 1) state [19], although here it appears as a ground state property (and only in the limit ωc  ω0 ). So far we have considered only the single-particle contribution to ...
GENERAL CHEMISTRY SECTION I: ATOMIC THEORY
GENERAL CHEMISTRY SECTION I: ATOMIC THEORY

... Many important theoretical and experimental results would follow from the discovery of the particle nature of light. • Matter also has a wave-particle duality. Turn about is fair play as deBroglie showed that matter, even people, have a wave-like nature. The deBroglie wave equation for matter is: “λ ...
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Harmonic oscillator

Unit 7 Chap. 7 Chemical Formulas and Compounds
Unit 7 Chap. 7 Chemical Formulas and Compounds

... 7. THE ALGEBRAIC SUM OF THE OXIDATION NUMBERS OF ALL ATOMS IN A NEUTRAL COMPOUND IS ZERO. 8. THE ALGEBRAIC SUM OF THE OXIDATION NUMBERS OF ALL ATOMS IN A POLYATOMIC ION IS EQUAL TO THE CHARGE OF THE ION. ...
Notes 12
Notes 12

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... 43. If |n> with n=0,1,2,3, .., are the eigenstates of the number operator Nˆ  aˆ  aˆ of a one-dimensional simple harmonic oscillator, calculate the matrices of the position operator X̂ and the momentum operator P̂ based on the basis set of{ |n >}. 44. Find the uncertainty relation between  , the ...
Interactions and Interference in Quantum Dots: Kinks in Coulomb
Interactions and Interference in Quantum Dots: Kinks in Coulomb

... dot is separated from an excited state with different spin by an energy of order ∆. The interference effects causing the separation are unique to each state and change upon tuning. In fact, the two states may switch at a certain point, the former excited state becoming the ground state: such switchi ...
Interactions and interference in quantum dots : kinks in
Interactions and interference in quantum dots : kinks in

... dot is separated from an excited state with different spin by an energy of order ∆. The interference effects causing the separation are unique to each state and change upon tuning. In fact, the two states may switch at a certain point, the former excited state becoming the ground state: such switchi ...
STRUCTURE OF A TURE OF A TURE OF ATOM STRUCTURE OF A
STRUCTURE OF A TURE OF A TURE OF ATOM STRUCTURE OF A

< 1 ... 111 112 113 114 115 116 117 118 119 ... 276 >

X-ray photoelectron spectroscopy



X-ray photoelectron spectroscopy (XPS) is a surface-sensitive quantitative spectroscopic technique that measures the elemental composition at the parts per thousand range, empirical formula, chemical state and electronic state of the elements that exist within a material. XPS spectra are obtained by irradiating a material with a beam of X-rays while simultaneously measuring the kinetic energy and number of electrons that escape from the top 0 to 10 nm of the material being analyzed. XPS requires high vacuum (P ~ 10−8 millibar) or ultra-high vacuum (UHV; P < 10−9 millibar) conditions, although a current area of development is ambient-pressure XPS, in which samples are analyzed at pressures of a few tens of millibar.XPS is a surface chemical analysis technique that can be used to analyze the surface chemistry of a material in its as-received state, or after some treatment, for example: fracturing, cutting or scraping in air or UHV to expose the bulk chemistry, ion beam etching to clean off some or all of the surface contamination (with mild ion etching) or to intentionally expose deeper layers of the sample (with more extensive ion etching) in depth-profiling XPS, exposure to heat to study the changes due to heating, exposure to reactive gases or solutions, exposure to ion beam implant, exposure to ultraviolet light.XPS is also known as ESCA (Electron Spectroscopy for Chemical Analysis), an abbreviation introduced by Kai Siegbahn's research group to emphasize the chemical (rather than merely elemental) information that the technique provides.In principle XPS detects all elements. In practice, using typical laboratory-scale X-ray sources, XPS detects all elements with an atomic number (Z) of 3 (lithium) and above. It cannot easily detect hydrogen (Z = 1) or helium (Z = 2).Detection limits for most of the elements (on a modern instrument) are in the parts per thousand range. Detection limits of parts per million (ppm) are possible, but require special conditions: concentration at top surface or very long collection time (overnight).XPS is routinely used to analyze inorganic compounds, metal alloys, semiconductors, polymers, elements, catalysts, glasses, ceramics, paints, papers, inks, woods, plant parts, make-up, teeth, bones, medical implants, bio-materials, viscous oils, glues, ion-modified materials and many others.XPS is less routinely used to analyze the hydrated forms of some of the above materials by freezing the samples in their hydrated state in an ultra pure environment, and allowing or causing multilayers of ice to sublime away prior to analysis. Such hydrated XPS analysis allows hydrated sample structures, which may be different from vacuum-dehydrated sample structures, to be studied in their more relevant as-used hydrated structure. Many bio-materials such as hydrogels are examples of such samples.
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