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تسجيل مستخدم جديدR-matrix electron-impact excitation data for the C-like iso-electronic sequence
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Emission and absorption features from C-like ions serve as temperature and density diagnostics of astrophysical plasmas. $R$-matrix electron-impact excitation data sets for C-like ions in the literature merely cover a few ions, and often only for the ground configuration. Our goal is to obtain level-resolved effective collision strength over a wide temperature range for C-like ions from ion{N}{II} to ion{Kr}{XXXI} (i.e., N$^{+}$ to Kr$^{30+}$) with a systematic set of $R$-matrix calculations. We also aim to assess their accuracy. For each ion, we included a total of 590 fine-structure levels in both the configuration interaction target and close-coupling collision expansion. These levels arise from 24 configurations $2l^3 nl^{prime}$ with $n=2-4$, $l=0-1$, and $l^{prime}=0-3$ plus the three configurations $2s^22p5l$ with $l=0-2$. The AUTOSTRUCTURE code was used to calculate the target structure. Additionally, the $R$-matrix intermediate coupling frame transformation method was used to calculate the collision strengths. We compare the present results of selected ions with archival databases and results in the literature. The comparison covers energy levels, transition rates, and effective collision strengths. We illustrate the impact of using the present results on an ion{Ar}{xiii} density diagnostic for the solar corona. The electron-impact excitation data is archived according to the Atomic Data and Analysis Structure (ADAS) data class adf04 and will be available in OPEN-ADAS. The data will be incorporated into spectral codes, such as CHIANTI and SPEX, for plasma diagnostics.
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Spectral lines from N-like ions can be used to measure the temperature and density of various types of astrophysical plasmas. The atomic databases of astrophysical plasma modelling codes still have room for improvement in their electron-impact excita
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Astrophysical plasma codes are built on atomic databases. In the current atomic databases, R-matrix electron-impact excitation data of O-like ions are limited. The accuracy of plasma diagnostics with O-like ions depends on the availability and accura
cy of the atomic data. This is particularly relevant in the context of future observatories equipped with the next generation of high-resolution spectrometers. To obtain level-resolved effective collision strengths of O-like ions from ion{Ne}{III} to ion{Zn}{XXIII} (i.e., Ne$^{2+}$ to Zn$^{22+}$) over a wide range of temperatures. This includes transitions up to $nl=5d$ for each ion. We also aim to assess the accuracy of the new data, as well as their impact on solar atmosphere plasma diagnostics, compared to those available within the CHIANTI database. A large-scale R-matrix intermediate coupling frame transformation calculations were performed systematically for the O-like iso-electronic sequence. For each ion, 630 fine-structure levels were included in both the configuration interaction target and close-coupling collision expansions. The present results (energy levels, oscillator strengths, and effective collision strengths) of selected ions across the iso-electronic sequence are compared with those in archival databases and the literature. For selected ions across the iso-electronic sequence. We find general agreement with the few previous R-matrix calculations of collision strengths. We illustrate the improvements for a few solar plasma diagnostics over existing CHIANTI atomic models based on distorted wave data. The electron-impact excitation data are archived according to the Atomic Data and Analysis Structure (ADAS) data class adf04 and will be available in OPEN-ADAS.
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