Abstract

Groups of iron lines with relative intensities independent of excitation are proposed to serve as intensity standards for rapid and reliable plate calibration. One such group between 3140 and 3240A has been tested under a great variety of conditions and found to be satisfactory for this purpose. Lines of Fe I selected at random in general have their relative intensities changed much more by self-reversal than by changes in excitation. A general quantitative study of self-reversal was made which allows an estimate of the degree of self-reversal of any line under given conditions. Weak or moderately strong lines coming down to all but the lowest levels are free from self-reversal under the conditions at which arcs or sparks are usually operated.

© 1943 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. H. H. Grossmann, R. A. Sawyer, and H. B. Vincent, J. Opt. Soc. Am. 33, 183 (1943). R. A. Sawyer and H. B. Vincent, ibid. 33, 247 (1943). The latter paper appeared while the present article was in press.
    [Crossref]
  2. K. Burns and F. H. Walters, Pub. Allegheny Obs. 6, 159 (1929); Pub. Allegheny Obs. 8, 43 (1931).
  3. Imperfect control of the primary calibration in the earlier experiments has caused the values of the intensities given in Table I to be slightly different from later values when these imperfections had been eliminated. This, however, has no influence on the comparison of the values taken under different conditions. Only the intensity scale used is different from the true one.
  4. See, e.g., R. Frerichs, Ann. d. Physik 81, 807 (1926); J. B. van Milaan, Zeits. f. Physik 34, 921 (1925).
    [Crossref]
  5. G. R. Harrison, J. Opt. Soc. Am. 17, 389 (1928); G. R. Harrison and H. Engwicht, J. Opt. Soc. Am. 18, 287 (1929).
    [Crossref]
  6. A simple consideration shows that in calculating the optical path length d we must disregard the a priori probability (2J+1) in the number of atoms. This factor is taken care of in I0. This can be easily seen if the J degeneracy is first removed (e.g., by a magnetic field).
  7. The scattering of the points in general is not due to accidental errors of measurement, but due to the fact that a fairly large wave-length interval was covered for which both the sensitivity and the contrast of the plate changed, which changes were not taken into account in the plate calibration.
  8. S. Levy, J. App. Phys. 11, 480 (1940).
    [Crossref]

1943 (1)

1940 (1)

S. Levy, J. App. Phys. 11, 480 (1940).
[Crossref]

1929 (1)

K. Burns and F. H. Walters, Pub. Allegheny Obs. 6, 159 (1929); Pub. Allegheny Obs. 8, 43 (1931).

1928 (1)

1926 (1)

See, e.g., R. Frerichs, Ann. d. Physik 81, 807 (1926); J. B. van Milaan, Zeits. f. Physik 34, 921 (1925).
[Crossref]

Ann. d. Physik (1)

See, e.g., R. Frerichs, Ann. d. Physik 81, 807 (1926); J. B. van Milaan, Zeits. f. Physik 34, 921 (1925).
[Crossref]

J. App. Phys. (1)

S. Levy, J. App. Phys. 11, 480 (1940).
[Crossref]

J. Opt. Soc. Am. (2)

Pub. Allegheny Obs. (1)

K. Burns and F. H. Walters, Pub. Allegheny Obs. 6, 159 (1929); Pub. Allegheny Obs. 8, 43 (1931).

Other (3)

Imperfect control of the primary calibration in the earlier experiments has caused the values of the intensities given in Table I to be slightly different from later values when these imperfections had been eliminated. This, however, has no influence on the comparison of the values taken under different conditions. Only the intensity scale used is different from the true one.

A simple consideration shows that in calculating the optical path length d we must disregard the a priori probability (2J+1) in the number of atoms. This factor is taken care of in I0. This can be easily seen if the J degeneracy is first removed (e.g., by a magnetic field).

The scattering of the points in general is not due to accidental errors of measurement, but due to the fact that a fairly large wave-length interval was covered for which both the sensitivity and the contrast of the plate changed, which changes were not taken into account in the plate calibration.

Cited By

OSA participates in Crossref's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (6)

Fig. 1
Fig. 1

Diagram of the low-lying energy levels of Fe I. The width is the total multiplet width. Scale in 1000 cm−1.

Fig. 2
Fig. 2

Self-reversal of Fe lines between 2900A and 3100A ending on the a5D and a5F levels. (d.c. arc, current 2 amp.)

Fig. 3
Fig. 3

Self-reversal of Fe lines in 8-amp. d.c. arc.

Fig. 4
Fig. 4

Self-reversal of a5F lines in 2-amp. d.c. arc.

Fig. 5
Fig. 5

Self-reversal of a5F lines in a.c. arc and spark.

Fig. 6
Fig. 6

Influence of air current produced by fan blowing away from slit on self-reversal of a5F lines.

Tables (1)

Tables Icon

Table I Log I values of Fe lines under various light source conditions.

Equations (8)

Equations on this page are rendered with MathJax. Learn more.

d = N r d r ,
I = I 0 e - a d ,
a = α I 0 ,
I = I 0 exp ( - α d I 0 ) .
log I / I 0 = - α d e x .
e - E / k T ,
log I 0 / I = b I 0 e - E / k T = β e x - ( E / k T ) ;             x = log I 0 ,
x - x = ( E - E ) / k T .