ner_tags: O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation O O B-Citation I-Citation I-Citation O O O B-Citation I-Citation I-Citation O O O O O B-Citation I-Citation I-Citation O O O B-Tag O O O O O O O O O O O O B-Citation I-Citation I-Citation I-Citation O O O O O O B-Citation I-Citation I-Citation I-Citation O O O B-Citation O O O O O O O O O O O B-Citation O B-Software O B-Software O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Software O O O O O B-Identifier I-Identifier O O O B-Citation O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation I-Citation O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation I-Citation I-Citation I-Citation O O O O O O O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation I-Citation I-Citation I-Citation O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Citation B-Citation I-Citation I-Citation I-Citation I-Citation I-Citation O O O O O O O O O O O O O O O O O O O O O O O B-Citation O B-Citation I-Citation I-Citation I-Citation I-Citation I-Citation O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Citation O O O B-Citation O O O O O B-Citation O O B-Citation I-Citation I-Citation O O O B-Citation I-Citation I-Citation O O O O B-Citation I-Citation I-Citation O O O B-Tag O O B-Tag O O O O O O O O O O O O
tokens: for the ground and metastable levels weighted by their experimental ion populations (76 per cent ground, 24 per cent metastable) is in good agreement with the experiment, particularly near the threshold and at higher energies. Interestingly, the area where the cross-section from this work lies outside the experimental uncertainty is at the energies just below the peak, where their experiment differs most with the adjusted Loch et al. results. Figure 5. Total collisional ionization cross-section for O v with 24 per cent metastable population; blue solid line: this work; blue dashed line: difference in cross-section owing to metastable population uncertainty; green dotted line: Dere (ground only); red dash–dotted line: Loch et al.; orange dashed line with circles: Fogle et al.; red circles: Loch et al. experiment; green triangles: Loch et al. experiment (adjusted); light blue squares: Fogle et al. experiment. 3.1.6 O <sc>vi</sc> The DI cross-section from this work is 5 per cent lower than Younger ( 1981a ) and 10 per cent lower than Dere ( 2007 ). The cross-section from Younger is obtained from the scaled cross-section for the isoelectronic sequence, while Dere uses FAC. Since FAC is used for the present work, also, and tests with different optimizations and configurations produces the same results, perhaps a possible explanation is that a different version of FAC may have been used here (v. 1.1.4) than used by Dere. Inner shell EA makes a notable contribution to the cross-section and has been clearly identified by experiment. The calculated EA cross-section is 25 per cent higher than Dere ( 2007 ), but this will not affect the rate coefficients substantially because the EA threshold is so much higher than that of DI. In comparison with experiment, the computed cross-section is favourable with the work of Rinn et al. ( 1987 ), lying close to it from threshold up to the peak, and thereafter the experiment is noticeably higher, as shown in Fig. 6 . The experiment of Defrance et al. ( 1990 ) has few data points at energies below the peak in cross-section, but this work does agree in that region. Above that, they lie higher than this work and their results are closer to Dere. Crandall et al. ( 1979 ) has a large uncertainty, which encompass all of the theoretical results in most cases. The rate coefficients are in very good agreement with Dere and Bell et al. ( 1983 ) for most of their range, and only differ at temperatures above 10 6 K, varying by 10–20 per cent. Figure 6. Total collisional ionization cross-section for O vi ground level; blue solid line: this work; blue dashed line: this work (DI only); green dashed line with circles: Dere; green dotted line: Dere (DI only); red dash–dotted line: Younger; green circles: Crandall et al. experiment; red triangles: Defrance et al. experiment; light blue squares: Rinn et al. experiment. 3.1.7 O <sc>vii</sc> and O <sc>viii</sc> The various DW calculations for He-like O vii are all in very