China Research Association of Atomic and Molecular Data

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China Research Association of Atomic and Molecular Data (CRAAMD) was initiated in 1987 with the objective to coordinate data compilation, evaluation and production. There are 10 active participating groups, listed here together with their principal contact person and area of interest. 1) Institute of Applied Physics and Computational Mathematics, Beijing, Yan Jun, theoretical calculation of atomic data and simulations of radiative properties of both LTE and non-LTE plasmas. 2) Institute of Modern Physics of the Chinese Academy of Sciences, Ma Xin-Wen, heavy particle collision experiments. 3) Graduate School of the Chinese Academy of Sciences, Qu Yi-Zhi, theoretical calculation of cross sections for heavy particle collision processes and data evaluation. 4) Fudan University, Chen Chong-Yang, electron-ion collision theory and experiment. 5) Sichuan University, An Zhu, measurements of atomic inner-shell ionization cross sections. 6) Jilin University, Ding Da-Jun, molecular spectra data compilation. 7) Science and Technology University of China, Zhu Lin-Fan, electron-atom and electron-molecule collision experiments. 8) National University of Defense Technology, Yuan Jian-Min, theoretical calculation of opacity of LTE plasmas based on DLA model. 9) Tsinghua University, Mo Yu-Xiang, ionization potential of molecule ions and vibrational and rotational resolved molecular spectra based on ZEKE facility. 10) Northwest Normal University, Dong Chen-Zhong, theoretical calculations of energy levels and radiative transition properties for M-shell Au ions.

The database work of CRAAMD is concentrated at the Atomic and Molecular Data Research Center in Beijing and is supported by the Institute of Applied Physics and Computational Mathematics (IAPCM) and by the Chinese National Committee for CODATA. The atomic and molecular databases may be accessed through The atomic database includes information about ionization potentials, levels, spectra, electron-impact excitation, electron-impact ionization, dielectronic recombination, autoionization, photoionization and opacity, and it has a bibliographical component. Sections on heavy particle collisions and quantum defects are planned. The molecular database includes information about ion-molecule and electron-molecule collisions. A section on molecular spectroscopy is planned. A set of generalized oscillator strength (GOS) and GOS density (GOSD) data for sodium was recommended by CRAAMD, which include the transition from the ground state [2p63s]3 2S excited to [2p6(n+1)s](n+1) 2S,[2p6np]n 2P,[2p6nd]n 2D (3≤n≤∞) and adjacent continuum states, as well as to some autoionization states. These data were calculated using modified R-matrix codes based on a set of elaborately optimized target orbital bases and were verified to be of high accuracy.

A large amount of data was produced by CRAAMD in past years. That brought forth an issue, which may be a general issue for data work, that it is almost impossible to evaluate all these data critically, especially the calculated data. (This also applies to on-line data calculations.) In principle, for sure, the recommended data should be reliable, like the NIST atomic spectroscopy data. On the other hand, these calculated data may provide a systemic collection consisting of energy levels and rate coefficients of all dynamic transition processes and covering the ground and excited states of many ionic stages. Such data may be very much of interest to users in astrophysics or fusion sciences for applications in plasma simulation and plasma diagnostics, even though we know that those calculated data are not very precise; for example, errors may be 10% to 30% compared with the measurements, and the accuracy may be even poorer for weak transitions. Therefore, one hesitates to include these data into the database, and many of the data produced by CRAAMD have not been included in its database. At present the principle of CRAAMD for including newly produced data is (1) to include all the critically assessed data, and (2) to include systemically calculated data, which must be sampling evaluated and for which evaluation reports must be provided to help the user judge the quality.

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