| 释义 |
parahelium
(stress variable)
Also parhelium.
[f. para-1 3 + helium.]
The form of helium whose spectrum does not exhibit the fine structure of orthohelium, owing to the spins of the two orbital electrons being anti-parallel.
1896Runge & Paschen in Astrophysical Jrnl. III. 18 We come to the conclusion that clèveite gas consists of two elements, one corresponding to the second and third series (single lines), and the other corresponding to the fifth and sixth series (double lines..). If this is true, the name Helium should be given only to the second element... The first element Professor Stoney has proposed to call Parhelium. 1903A. M. Clerke Probl. Astrophysics v. 58 ‘Parhelium’ may then safely be treated as fictitious. 1922,1961[see orthohelium]. 1974G. Reece tr. Hund's Hist. Quantum Theory iv. 60 Runge and Paschen were able to add series for O, S, Se and He in 1895–7. They discovered the two spectral systems of orthohelium and parahelium in the process. |