The exact way how a guitar's string vibrates depends on the spot where it has been plucked. Some simple examples will be used to demonstrate general properties of oscillating systems, standing waves in particular. For us it is important to realize that the electron forms some kind of standing wave. This is described in detail in all textbooks on quantum mechanics. Its possible wavefunctions can be obtained as solutions of the Schrödinger equation. Its nucleus carries one unit of positive elementary charge and thus binds only one electron to it. The hydrogen atom is the simplest of all atoms. Wavefunctions are used to calculate observable quantities in particular, the probability to find the (pointlike) particle in some volume is given by the squared value of the wavefunction integrated over the volume. Thus the electrons bound by electric force to an atomic nucleus (which contains almost all of the atom's mass) must be considered to be waves. The fact that these apparently contradictory attributes are compatible in matter waves and also in light (photons) is hard to understand, but all experimental data point out that this is the case. Waves always have some spatial extension, while one may imagine the elementary, indivisible particles as being “pointlike”. While we cannot dive into mathematical details here, the basic principles shall be sketched. Quantum theory is, so to say, the mathematical formulation of particle–wave duality. Only with quantum theory atomic structure can be understood. Nevertheless, to understand how the colours which surround us come about, one needs some basic knowledge on the smallest parts of matter. If the light of the sun is spread out into different colours by a simple glass prism, the narrow absorption lines cannot be seen. Neon, which gives red colour in a gas discharge, is a colourless gas. The aurora borealis (northern light) is very rare at our latitudes, and to appreciate the colours of cosmic objects, powerful telescopes are necessary. Neon signs (or other gas discharge tubes) as used for advertising, sodium or mercury vapour lamps show atomic emission the colours of fireworks are due to it. Light emitted or absorbed by single atoms contributes only very little to the colours of our surroundings. The same file with adapted formatting can be found here. Department of Energy, by the National Aeronautics and Space Administration, by NIST's Standard Reference Data Program (SRDP), and by NIST's SMA Program.Atomic spectra The html formatting and custom instructions have been disabled on this server. This database was funded by the Office of Fusion Energy Sciences of the U.S. Online: March 1995 - Last update: December 2023 All rights reserved. NIST reserves the right to charge for these data in the future. Department of Commerce on behalf of the United States. Past Contributors: Haris Kunari, Jean E. Sansonetti, Jeffrey R. Fuhr, Larissa I. Podobedova, Wolfgang L. Wiese, John J. Curry, Gerry R. Dalton, Robert Dragoset, Fun-Chen (Jesse) Jou, William C. Martin, Peter J. Mohr, Arlene Musgrove, Craig J. Sansonetti, and Gloria Wiersma Students contributing to data entry: Eric Carpentier, Thomas Carpentier, Amy Zimmerman, Adrian Hamins-Puertolas, Marko Hamins-Puertolas, Anna Sharova, Genevieve Tan NIST ASD Team Principal Developers (Currently Active): Alexander Kramida, Yuri Ralchenko, and Joseph Readerĭata Compilers (Currently Active): Alexander Kramida, Edward B. Salomanĭatabase Developers (Currently Active): Alexander Kramida, Yuri Ralchenko, and Karen Olsen The Data Center is located in the Physical Measurement Laboratory at the National Institute of Standards and Technology (NIST). The Atomic Spectroscopy Data Center has carried out these critical compilations. This database provides access and search capability for NIST critically evaluated data on atomic energy levels, wavelengths, and transition probabilities that are reasonably up-to-date. Help - On-line help in using the database. Synchrotron Ultraviolet Radiation Facility SURF IIIĪSD Interface for Laser Induced Breakdown Spectroscopy (LIBS)Īdditional information about the database may be obtained through the following links:Ītomic Spectroscopy Intro - Outlines basic atomic physics concepts, explains terminology and notation.ĪSD Intro & Contents - Introduction to and contents of the Atomic Spectra Database.īibliography - Bibliography of data sources used for this database.Radiopharmaceutical Standardization Laboratory.Calibrations Customer Survey (external link).
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