Portal for High-Precision Atomic Data and Computation
To fulfil the ever growing demand of atomic properties by astro, plasma, nuclear, particle physicists and engineers, an easy-to-use online portal has been developed with collaborative efforts by researchers at the University of Delaware, USA and Guru Nanak Dev University, India. The portal is available at “http://www1.udel.edu/atom/". The goal of this project is to provide the scientific community with easily accessible high-quality atomic data and user-friendly, broadly-applicable modern relativistic codes. This online portal is an effort to provide much-needed precise atomic properties like transition matrix elements, transition rates, radiative lifetimes, branching ratios, and polarizabilities for a number of atoms and ions. The data are calculated using a high-precision state-of-the-art linearized coupled-cluster method. Experimental values are included with references where high-precision data are available. All values include estimated uncertainties.
The portal contains following pages:
Homepage, which provides information of various properties for elements which are part of the project. The page also contains a short site tour and information about the current and upcoming versions.
About the project page, containing more information about the data and the method used. It can be accessed by clicking on the “Learn more” button present at bottom of the Homepage.
Matrix element page contains dipole matrix elements for a number of transitions in all alkali atoms and alkaline earth ions, element wise. Page has a Print button to print the tables and an Excel button to download the data. Note that the downloaded file also contain separate columns for the values and uncertainties for all properties.
Transition rates page contains E1 transitions rates for a number of transitions in all alkali atoms and alkaline earth ions, element wise. All contributing E1 transition rates and respective branching ratios, matrix elements and wavelengths are listed for convenience in the same page. Page has a Print button to print the tables and an Excel button to download the data.
Polarizabilities page contains information about static dipole polarizabilities for a number of states and dipole polarizability graphs for the ns1/2 and np1/2,3/2 (where n is the valence state of the considered element). The graphs can be saved in png format. One can also download the data used to plot the graphs.
Other data page contains nuclear data and Hyperfine constants for the considered elements. For atoms/ions having a metastable states the same page contains data for electric quadrupole (E2) and magnetic dipole (M1) transitions, lifetimes, and quadrupole moments. At present this page contains some information which has been extracted from a number of other sources. Appropriate references for the data for other sources have been cited. The tables in this page can be printed by clicking on the print screen button.
Citation info page contains citation information for the webpage. A format for bibtex referencing is also provided for convenience.
Feedback page contains a feedback form which can be used by users to send feedback for further improvement of the portal. The feedback can also be sent at atom-feedback@udel.edu. Before sending feedback it is recommended that users read our received feedback and upcoming changes and features page to make sure that the feedback.
Each page contains a Help button to help browse through the page. Data for more systems will be added in the future. Future updates will also include releases of user-friendly atomic codes. The data from the portal will benefit the research community working in the fields of quantum information, degenerate quantum gases, atomic clocks, precision measurements of atoms and molecules, plasma physics, astrophysics, and studies of fundamental physics.
Method used: A linearized coupled-cluster method is used to calculate the atomic properties of atoms and ions with one valence electron (monovalent systems). This method is also referred to as “all-order” in the literature as it involves summing series of dominant many-body perturbation terms to all orders. In the single-double (SD) all-order approach, single and double excitations of the Dirac-Fock orbitals are included. The SDpT all-order approach also includes classes of the triple excitations. Omitted higher excitations are estimated by the scaling procedure which can be started from either SD or SDpT approximations. We carry out four all-order computations for each of the electric-dipole matrix elements, ab initio SD and SDpT and scaled SD and SDpT. Either SD or SD scaled data are taken as final values based on the comparison of different contributions to the matrix elements. An algorithm is used to determine the uncertainties of the electric-dipole matrix elements based on the spread of the four results, size of the correlation correction, and comparison of different contributions to the matrix elements. More information regarding the method used can be found in Advances in Atomic Molecular and Optical Physics series, volume 55, 194 (2007) and Phys. Rev. A 77, 022510 (2008).