Abstract

The absolute ƒ-values of rotational lines in the positive and negative branches of the 2ν<sub>3</sub> overtone band of CH<sub>4</sub> have been derived from absorption measurements in the laboratory by two independent methods. The first method involves the use of the curve of growth and requires the observation of weak lines for which the total absorption is independent of the damping constant. In the second method the lines are broadened artificially, by the introduction of about 3 atmos of air, to half-widths that are about five times the slit width. The ƒ-values are then determined by integration of the logarithm of the percentage absorption over the line profile. On the average, the ƒ-values obtained by the two methods agree within 10 percent.

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  1. Robert R. McMath and Orren C. Mohler, J. Opt. Soc. Am. 39, 903 (1949).
  2. E. B. Wilson, Jr., and A. J. Wells, J. Chem. Phys. 14, 578 (1946).
  3. D. M. Dennison, Phys. Rev. 31, 503 (1928).
  4. A. Unsöld, Pysik der Sternatmosphären (Verlag. Julius Springer, Berlin, 1938), p. 165.
  5. Actually, the collisional damping may be expected to increase slightly with excitation potential, since, owing to the interaction between rotation and vibration, the internuclear distance and therefore the target area for collision increases with increasing rotation. But the effect is negligibly small.
  6. G. Herzberg, Infra Red and Raman Spectra (D. van Nostrand Company, Inc., New York, 1945), p. 451.
  7. See reference 6, p. 506.
  8. W. H. J. Childs and H. A. Jahn, Proc. Roy. Soc. (London) A169, 451 (1939).

Childs, W. H. J.

W. H. J. Childs and H. A. Jahn, Proc. Roy. Soc. (London) A169, 451 (1939).

Dennison, D. M.

D. M. Dennison, Phys. Rev. 31, 503 (1928).

Herzberg, G.

G. Herzberg, Infra Red and Raman Spectra (D. van Nostrand Company, Inc., New York, 1945), p. 451.

Jahn, H. A.

W. H. J. Childs and H. A. Jahn, Proc. Roy. Soc. (London) A169, 451 (1939).

McMath, Robert R.

Robert R. McMath and Orren C. Mohler, J. Opt. Soc. Am. 39, 903 (1949).

Mohler, Orren C.

Robert R. McMath and Orren C. Mohler, J. Opt. Soc. Am. 39, 903 (1949).

Unsöld, A.

A. Unsöld, Pysik der Sternatmosphären (Verlag. Julius Springer, Berlin, 1938), p. 165.

Wells, A. J.

E. B. Wilson, Jr., and A. J. Wells, J. Chem. Phys. 14, 578 (1946).

Wilson, Jr., E. B.

E. B. Wilson, Jr., and A. J. Wells, J. Chem. Phys. 14, 578 (1946).

Other (8)

Robert R. McMath and Orren C. Mohler, J. Opt. Soc. Am. 39, 903 (1949).

E. B. Wilson, Jr., and A. J. Wells, J. Chem. Phys. 14, 578 (1946).

D. M. Dennison, Phys. Rev. 31, 503 (1928).

A. Unsöld, Pysik der Sternatmosphären (Verlag. Julius Springer, Berlin, 1938), p. 165.

Actually, the collisional damping may be expected to increase slightly with excitation potential, since, owing to the interaction between rotation and vibration, the internuclear distance and therefore the target area for collision increases with increasing rotation. But the effect is negligibly small.

G. Herzberg, Infra Red and Raman Spectra (D. van Nostrand Company, Inc., New York, 1945), p. 451.

See reference 6, p. 506.

W. H. J. Childs and H. A. Jahn, Proc. Roy. Soc. (London) A169, 451 (1939).

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