4 Results and conclusions

Table 1 summarizes this work result, including the ratios with the literature collected values.

The uncertainty for each A_ki value of this experiment which can be estimated by the standard deviation that shows the different 15 experimental values for each line, is showed in percentages. Although with a clear dependence on the line, usually uncertainties in this work are around 10%. For instance, Fig. 6 shows the different A_ki-values measured for two NII measured lines.

Figure 6: An example of Aki data of this work versus time of the plasma life for two NII lines. No trends are observed. The data of NII 571.08 nm line are in good agreement within 10% uncertainties with the NIST value compiled by Wiese et al. 1996 (with 3% accuracy). In the case of NII 455.25 nm line this work data (also with uncertainty of 10%) show differences around 20% with available NIST value. This can be explained taking into account that NIST data base value is within 30% accuracy in this case

Figure 7 shows the relative differences between the NIST values taken from literature as reference to determine NII excitation temperature from Boltzmann-plots, and this work for each line, as a function of wavelength. As can be seen, almost 80% of the data show differences below 15%. Usually NIST critical compilation assigned uncertainties around 10% to their values (in some cases around 30%). Taking into account this uncertainty and the statistical uncertainties assigned to each line in this work, the agreement is good. Also, Fig. 7 shows that there is no systematic trends in this experiment with wavelength, which gives an idea of the good spectral intensity calibration performed.

Figure: Relative differences between this work Aki values and NIST tabulated ones, taken as reference, versus $\lambda$. No trends are detected and 77% of the data differ less than 15%

As to the other literature collected data, the agreement is also good. The uncertainties of Musielok et al. work are also around 10%, while the differences with theoretical values reported by Lavin et al. (1999) working with a Relativistic Quantum Defect Orbital (RQDO) method with explicit polarization correction are also within a 10% error band. As can be seen in the table, the ratios between this work values and those of Musielok et al. tend to be systematically different within some multiplets. Greater in the $\rm ^3P-^3D^0$ multiplet of the 3p-3d transitions, and lower in the $\rm ^3P^0-^3P$ multiplet of the 3s-3p transitions. These tendencies are not so clear in ratios with NIST data. Perhaps differences could be partially explained by the different method used by Musielok et al. to put their measured line data on an absolute basis. Anyway, the very careful spectral calibration used in this work excludes systematic errors due to wavelength dependencies.

The 7 values quoted with * in the column Tw/NIST need a special comment. Although they have been obtained from NIST Standard Reference Database 61 (1995), with the following reference: Fuhr J. & Wiese W.L. "Atomic Transition Probabilities" in the CRC Handbook of Chemistry and Physics, chapter 10, (ed.) D.R. Lide (1995), they do not appear reflected in the Wiese et al. (1996) critical compilation. Besides NIST Database has assigned 30% uncertainties to these 7 lines. So they have not been used in the Boltzmann-plot temperature calculations in the present work. Their results show the greatest discrepancies. In the case of NII 405.69 nm line, this work result differ by a factor greater than 8. Perhaps an edition mistake in one order of magnitude could explain this.

As conclusion the main advantages of this experiment are the following:

a) About the 75% of the 95 spectral lines, whose data can be compared, agree both with the recent theoretical and experimental available data, assuming error bands around 10% in the considered works;

b) This work shows the coherence of a unique emission experiment, very carefully performed and with a good plasma diagnostics, which furnishes a great number of data for each line, and that for many lines; c) Finally, this experiment improves the knowledge of A_ki-values for 13 new lines where we have not found previous references.

 

 

Table: A_ki-values from this work arranged by wavelength. All values must be multiplied by 10⁸ s^-1, and uncertainties $\sigma$ are given in percentage. In the last three columns appear ratios between this work results Tw, and the available literature: NIST tabulated data by Wiese et al. (1996), Experimental data of Musielok et al. (1996) and theoretical calculations by RQDO treatment of Lavín et al., private communication (1999)

$\lambda$	Transition	Multiplet	Ji-Jk	Aki	$\sigma$	Tw/NIST	Tw/Musielok	Tw/RQDO
(nm)				This work	(%)	ratio	ratio	ratio
382.98	3p-4s	$\rm ^3P-^3P^0$	1 - 2	0.223	16	0.92
383.84	3p-4s	$\rm ^3P-^3P^0$	2 - 2	0.639	6	0.92
384.22	3p-4s	$\rm ^3P-^3P^0$	0 - 1	0.314	11	1.03
384.74	3p-4s	$\rm ^3P-^3P^0$	1 - 1	0.216	12	0.97
385.51	3p-4s	$\rm ^3P-^3P^0$	1 - 0	0.935	20	1.06
385.61	3p-4s	$\rm ^3P-^3P^0$	2 - 1	0.343	7	0.93
391.90	3p-3d	$\rm ^1P-^1P^0$	1 - 1	0.559	10	0.83		0.73
395.59	3s-3p	$\rm ^3P^0-^1D$	1 - 2	0.129	11	0.99	0.97
399.50	3s-3p	$\rm ^1P^0-^1D$	1 - 2	1.320	11	0.98		1.01
402.61	3d-4f	$\rm ^3F^0-G(9/2)$	3 - 4	0.672	15	0.75*
403.51	3d-4f	$\rm ^3F^0-G(7/2)$	2 - 3	1.300	7
404.13	3d-4f	$\rm ^3F^0-G(9/2)$	4 - 5	2.080	10	0.79*
404.35	3d-4f	$\rm ^3F^0-G(7/2)$	3 - 4	1.250	25	0.51*
404.48	3d-4f	$\rm ^3F^0-G(7/2)$	3 - 3	0.214	39
405.69	3d-4f	$\rm ^3F^0-G(7/2)$	4 - 4	0.199	20	0.12*
407.30	3d-4f	$\rm ^3F^0-F(7/2)$	2 - 3	0.499	19
407.69	3d-4f	$\rm ^3F^0-F(5/2)$	2 - 2	0.080	42
408.23	3d-4f	$\rm ^3F^0-F(7/2)$	3 - 4	0.335	16
413.18	3d-4f	$\rm ^1D^0-G(7/2)$	2 - 3	0.204	13
413.37	3s-3p	$\rm ^5P-^5S^0$	2 - 2	0.398	11	0.75
414.58	3s-3p	$\rm ^5P-^5S^0$	3 - 2	0.605	15	0.82
417.16	3d-4f	$\rm ^1D^0-F(7/2)$	2 - 3	0.448	11
417.36	3d-4f	$\rm ^3D^0-D(5/2)$	2 - 2	0.120	30
417.62	3d-4f	$\rm ^1D^0-F(5/2)$	2 - 3	1.130	19	0.52*
417.97	3d-4f	$\rm ^3D^0-D(5/2)$	3 - 3	0.470	23
441.71	3d-4f	$\rm ^3P^0-D(3/2)$	2 - 2	0.233	14
442.72	3d-4f	$\rm ^3P^0-D(3/2)$	1 - 2	0.568	50
444.20	3d-4f	$\rm ^3P^0-D(5/2)$	1 - 2	0.695	16
444.70	3p-3d	$\rm ^3D-^3D^0$	1 - 2	1.210	9	1.06		0.93
450.76	3p-3d	$\rm ^3D-^3P^0$	3 - 2	0.109	6	1.09
453.04	3d-4f	$\rm ^1F^0-G(9/2)$	3 - 4	1.450	20	0.86*
455.25	3d-4f	$\rm ^1F^0-G(7/2)$	3 - 4	0.611	9	0.80*
456.48	3p-3d	$\rm ^1P-^3F^0$	1 - 2	0.019	16	1.36
460.15	3s-3p	$\rm ^3P^0-^3P$	1 - 2	0.190	9	0.81	0.69	0.86
460.72	3s-3p	$\rm ^3P^0-^3P$	0 - 1	0.297	8	0.91	0.76	0.95
461.39	3s-3p	$\rm ^3P^0-^3P$	1 - 1	0.199	4	0.88	0.74	0.91
462.14	3s-3p	$\rm ^3P^0-^3P$	1 - 0	0.882	8	0.92	0.80	0.95
463.05	3s-3p	$\rm ^3P^0-^3P$	2 - 2	0.775	7	1.00	0.88	1.12
464.31	3s-3p	$\rm ^3P^0-^3P$	2 - 1	0.477	7	1.06	0.94	1.25
465.45	3s-3p	$\rm ^1P^0-^3P$	1 - 2	0.022	11	0.92	0.82
469.46	3d-4f	$\rm ^1P^0-D(5/2)$	1 - 2	0.607	12
471.84	3p-3d	$\rm ^5D^0-^5D$	4 - 4	0.295	4	0.98
472.16	3p-3d	$\rm ^5D^0-^5D$	4 - 3	0.110	11	1.41
477.42	3p-3d	$\rm ^3D-^3D^0$	1 - 2	0.032	11	1.00	0.82	0.80
477.97	3p-3d	$\rm ^3D-^3D^0$	1 - 1	0.248	6	0.98	1.06	0.91
478.12	3p-3d	$\rm ^3D-^3D^0$	2 - 3	0.021	12	1.00	0.84	0.70
478.81	3p-3d	$\rm ^3D-^3D^0$	2 - 2	0.250	5	0.99	0.97	1.00
479.37	3p-3d	$\rm ^3D-^3D^0$	2 - 1	0.090	5	1.15	1.06	1.00
480.33	3p-3d	$\rm ^3D-^3D^0$	3 - 3	0.349	4	1.10	1.02	1.09
481.03	3p-3d	$\rm ^3D-^3D^0$	3 - 2	0.056	14	1.17	1.02	1.00
486.02	3p-3d	$\rm ^3D-^1D^0$	1 - 2	0.017	5	1.06
489.51	2p3-3p	$\rm ^1D^0-^1P$	2 - 1	0.044	15	1.02

 

Table 2: Continued from Table 1

$\lambda$	Transition	Multiplet	Ji-Jk	Aki	$\sigma$	Tw/NIST	Tw/Musielok	Tw/RQDO
(nm)				This work	(%)	ratio	ratio	ratio
498.74	3p-3d	$\rm ^3S-^3P^0$	1 - 0	0.586	13	0.78	0.78
499.12	3s-3p	$\rm ^5P-^5P^0$	1 - 2	0.325	35	0.92
499.44	3p-3d	$\rm ^3S-^3P^0$	1 - 1	0.738	5	0.97	0.96	0.98
500.51	3s-3p	$\rm ^5P-^5P^0$	2 - 2	1.220	7	1.05	0.95	0.97
500.73	3p-3d	$\rm ^3S-^3P^0$	1 - 2	0.844	8	1.07	1.08	1.13
501.64	3p-3d	$\rm ^3D-^3F^0$	2 - 2	0.186	5	1.15	1.01	0.96
502.30	3s-3p	$\rm ^5P-^5P^0$	3 - 2	0.359	15	0.99
502.57	3p-3d	$\rm ^3D-^3F^0$	3 - 3	0.118	11	1.10	1.01	1.15
504.51	3s-3p	$\rm ^3P^0-^3S$	2 - 1	0.369	8	1.08	1.11	0.98
507.36	3s-3p	$\rm ^1P^0-^3S$	1 - 1	0.029	7	1.12	1.07
518.32	3p-3d	$\rm ^5P^0-^5D$	3 - 3	0.335	30	1.16
519.04	3p-3d	$\rm ^5D^0-^5F$	4 - 4	0.156	16	0.88
531.34	3p-3d	$\rm ^5P^0-^5P$	1 - 1	0.147	8	1.04
532.02	3p-3d	$\rm ^5P^0-^5P$	2 - 1	0.382	15	0.91
532.10	3p-3d	$\rm ^5P^0-^5P$	1 - 2	0.274	11	1.09
533.87	3p-3d	$\rm ^5P^0-^5P$	2 - 3	0.260	13	1.41
534.02	3p-3d	$\rm ^5P^0-^5P$	3 - 2	0.200	21	0.77
535.12	3p-3d	$\rm ^5P^0-^5P$	3 - 3	0.317	19	0.86
545.21	3p-3d	$\rm ^3P-^3P^0$	0 - 1	0.087	12	0.98	1.09	0.78
545.42	3p-3d	$\rm ^3P-^3P^0$	1 - 0	0.302	6	0.90	0.98	0.90
546.26	3p-3d	$\rm ^3P-^3P^0$	1 - 1	0.103	6	1.03	1.08	1.23
547.53	3s-4p	$\rm ^1D^0-^1D$	2 - 2	0.047	32	1.00
547.81	3p-3d	$\rm ^3P-^3P^0$	1 - 2	0.052	11	1.08	1.11	0.63
548.01	3p-3d	$\rm ^3P-^3P^0$	2 - 1	0.141	7	1.09	1.24	1.01
549.57	3p-3d	$\rm ^3P-^3P^0$	2 - 2	0.262	5	1.09	1.16	1.06
552.62	3s-3p	$\rm ^5P-^5D^0$	1 - 2	0.179	13	0.84
553.02	3s-3p	$\rm ^5P-^5D^0$	2 - 3	0.356	18	0.88
554.01	3s-3p	$\rm ^5P-^5D^0$	1 - 2	0.745	19	1.24
554.35	3s-3p	$\rm ^5P-^5D^0$	2 - 2	0.340	11	0.97
566.66	3s-3p	$\rm ^3P^0-^3D$	1 - 2	0.327	10	0.87	1.00	0.91
567.60	3s-3p	$\rm ^3P^0-^3D$	0 - 1	0.304	6	1.03	1.13	1.15
567.96	3s-3p	$\rm ^3P^0-^3D$	2 - 3	0.492	9	0.94	1.02	1.04
568.62	3s-3p	$\rm ^3P^0-^3D$	1 - 1	0.215	10	1.11	1.21	1.09
571.08	3s-3p	$\rm ^3P^0-^3D$	2 - 2	0.140	10	1.13	1.23	1.19
573.07	3s-3p	$\rm ^3P^0-^3D$	2 - 1	0.018	12	1.39	1.29	1.39
592.78	3p-3d	$\rm ^3P-^3D^0$	0 - 1	0.346	3	1.08	1.23	1.33
593.18	3p-3d	$\rm ^3P-^3D^0$	1 - 2	0.473	4	1.11	1.33	1.34
594.02	3p-3d	$\rm ^3P-^3D^0$	1 - 1	0.289	7	1.28	1.74	1.48
594.17	3p-3d	$\rm ^3P-^3D^0$	2 - 3	0.659	5	1.19	1.41	1.41
595.24	3p-3d	$\rm ^3P-^3D^0$	2 - 2	0.147	5	1.16	1.47	1.27
595.43	3d-4p	$\rm ^1P^0-^1S$	1 - 0	0.508	14	1.03
615.08	3d-4p	$\rm ^3F^0-^3D$	2 - 2	0.026	4	0.90
616.78	3d-4p	$\rm ^3F^0-^3D$	4 - 3	0.311	9	1.17
617.02	3d-4p	$\rm ^3F^0-^3D$	2 - 1	0.288	14	1.01
617.33	3d-4p	$\rm ^3F^0-^3D$	3 - 2	0.345	12	1.32
634.06	3d-4p	$\rm ^3D^0-^3P$	3 - 2	0.199	16	0.93
634.69	3d-4p	$\rm ^3D^0-^3P$	1 - 1	0.067	20	0.97
637.96	3s-3p	$\rm ^3P^0-^1P$	1 - 1	0.049	10	0.80	0.80
648.21	3s-3p	$\rm ^1P^0-^1P$	1 - 1	0.333	7	1.11		1.03
650.46	3d-4p	$\rm ^3D^0-^3D$	3 - 3	0.062	10	1.17
661.06	3p-3d	$\rm ^1D-^1F^0$	2 - 3	0.647	10	1.02		1.01
661.36	4s-3s	$\rm ^3P^0-^3P$	2 - 2	0.219	34	1.39
662.98	3d-4p	$\rm ^1D^0-^1P$	2 - 1	0.291	19	1.08
663.48	4s-3s	$\rm ^3P^0-^3P$	2 - 1	0.091	10	1.03
681.00	3d-4p	$\rm ^3P^0-^3S$	2 - 1	0.231	6	1.00
683.41	3d-4p	$\rm ^3P^0-^3S$	1 - 1	0.158	21	0.97

Acknowledgements

We thank S. González for his work in the experimental device. the Dirección General de Investigación Científica y Técnica (Ministerio de Educación y Ciencia) of Spain for its financial support under Contract No. PB-98-0356. and also the Consejería de Educación y Cultura de la Junta de Castilla y León (VA23-99). Dr. J.A. Aparicio wants to express his personal acknowledgement to the Organización Nacional de Ciegos de Espana (ONCE) for its help.