Article records
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A Caltech Library Repository Feedhttp://www.rssboard.org/rss-specificationpython-feedgenenTue, 28 Nov 2023 17:14:52 +0000The fine structure of the helium arc spectrum
https://resolver.caltech.edu/CaltechAUTHORS:HOUpnas27
Authors: Houston, William V.
Year: 1927
Ever since its discovery the spectrum of helium has been thought to consist of singlets and doublets. Recently, however, spectroscopic theory has indicated that it should consist of singlets and triplets since helium is a two-electron system. Various attempts have been made to resolve the doublets into triplets,(1) but up to the present there have been no conclusive results. Within the last few months interest has been revived in these lines by the theoretical work of Heisenberg,(2) which predicts a triplet structure with unusual separation ratios. It is now possible to show that the helium lines really have a structure similar to that predicted by Heisenberg.https://authors.library.caltech.edu/records/bfjh4-df104A compound interferometer for fine structure work
https://resolver.caltech.edu/CaltechAUTHORS:HOUpr27a
Authors: Houston, William V.
Year: 1927
DOI: 10.1103/PhysRev.29.478
The overlapping of orders in a Fabry-Perot interferometer can be avoided by using two interferometers in series. The fundamental equation shows that the dispersion is independent of the plate separation, while the distance between orders is inversely proportional to it. Thus an instrument with a small separation may be used as a preliminary filter to eliminate some of the orders in one of larger separation. This will not affect the fine structure pattern, and the resolution will be even greater than that due to the larger separation. Such an instrument has been built and satisfies the predictions of the theory. A plate, taken with the green line of mercury, is shown to illustrate the effect of the preliminary interferometer.https://authors.library.caltech.edu/records/v176y-4rc38A spectroscopic determination of e/m
https://resolver.caltech.edu/CaltechAUTHORS:HOUpr27b
Authors: Houston, William V.
Year: 1927
DOI: 10.1103/PhysRev.30.608
Rydberg constants for hydrogen and helium.—By an interferometer method the wave-lengths of the hydrogen lines at 6563A and 4861A were measured with reference to λ5015.6750 of He as standard. The values so obtained were, for the doublet at 6563A, 6562.7110±.0018 and 6562.8473±.0009; and for the doublet at 4861, 4861.2800±.0013 and 4861.3578±0022. Similarly the wave-lengths of the 4686 lines of ionized helium were found to be 4685.7030±.0012 and 4685.8030±.0026. From these values of the wave-lengths the Rydberg constant for hydrogen, RH is calculated to be 109,677.759±.008, and the Rydberg constant for helium, RHe, to be 109, 722.403±.004.
Calculation of e/m.—The ratio of the mass of the electron to the mass of the hydrogen nucleus, m/mH, is given by m/mH=(RHe-RH)(mHe-m)/RH(mHe-mH)=1.33648(RHe-RH)/RH. The value of e/m is given in terms of the Faraday constant as e/m=(mH/m)(F/mH). If the values of RH and RHe calculated above be substituted in these expressions and if it be assumed that F=96470 abamp. per gr. mol. and mH=1.0072, it is found that e/m has the value (1.7606±.0010)×10^(7) e.m.u. per gr.https://authors.library.caltech.edu/records/89ptd-q6f49The temperature dependence of electron emission under high fields
https://resolver.caltech.edu/CaltechAUTHORS:HOUpr29a
Authors: Houston, William V.
Year: 1929
DOI: 10.1103/PhysRev.33.361
An expression showing the temperature dependence of electron emission under high fields is secured by combining the results of Fowler and Nordheim with the Fermi distribution of velocities used in the Sommerfeld electron theory of metals. The result is similar to that obtained previously by considering the diminution of the work function by the field. The temperature variation is small and decreases as the external field increases. It is of the right order of magnitude to agree with the most recent observations.https://authors.library.caltech.edu/records/q9eyf-5t603Some relationships between singlets and triplets in the spectra of two electron systems
https://resolver.caltech.edu/CaltechAUTHORS:HOUpr29b
Authors: Houston, William V.
Year: 1929
DOI: 10.1103/PhysRev.33.297
The Darwin-Pauli treatment of the electron is applied to the Schroedinger equation for a two electron system. The results show that the division into singlets and triplets is justified only as a limiting case. Expressions are derived which give the position of the levels, the Zeeman effect pattern, and the intensities of the lines when the division into singlet and triplet cannot strictly be made. These expressions are shown to give the observed facts of several spectra.https://authors.library.caltech.edu/records/1y9cr-snv05The temperature dependence of electrical conductivity
https://resolver.caltech.edu/CaltechAUTHORS:HOUpr29c
Authors: Houston, William V.
Year: 1929
DOI: 10.1103/PhysRev.34.279
To explain the fact that the resistance of a pure metal becomes zero at the absolute zero of temperature it is necessary to take into account the restrictions placed upon the electron scattering by the quantum statistics. When these are included as a probability of transition, the Brillouin treatment of wave scattering gives a very satisfactory law of the temperature dependence of resistance.https://authors.library.caltech.edu/records/0rvvp-jaz49The appearance of "forbidden lines" in spectra
https://resolver.caltech.edu/CaltechAUTHORS:HUFpr30
Authors: Huff, L. D.; Houston, W. V.
Year: 1930
DOI: 10.1103/PhysRev.36.842
A rough calculation shows that the quadrupole term in the radiation of a forbidden line is usually larger than the dipole produced by an external electric field. This is not true, however, when there is an intermediate state, with which both initial and final states combine, and which lies close to one of them.
If the J selection rule is violated, and the Laporte rule is obeyed, the radiation cannot be due to the quadrupole term and must be ascribed to the octopole. Hg 2270 is such a line. An octopole transition will have a Zeeman effect distinctively different from that of a dipole or quadrupole.https://authors.library.caltech.edu/records/w0w6d-1cj28A New Determination of e/m from the Zeeman Effect
https://resolver.caltech.edu/CaltechAUTHORS:CAMpr32
Authors: Campbell, J. S.; Houston, W. V.
Year: 1932
DOI: 10.1103/PhysRev.39.601
Values of e/m have been determined from the Zeeman separations of the Cd line 6439 and the Zn line 6362. For these lines the g-factors can be accurately determined from the theory. A magnetic field of 7300 gauss was produced by an air core solenoid in which the variation of field strength over a length of 6 cm at the center was less than 0.1 percent. The field to current ratio, K, of this solenoid was determined in terms of the calculated ratios of three single layer standard solenoids. The field strength during an exposure was then given by the product of this constant and the current flowing. Evaporation of Zn and Cd in the short (6 cm) positive column of a helium discharge tube gave the desired lines. The Zeeman patterns were photographed with a Fabry-Perot interferometer. The result is e/m = 1.7579 ± 0.0025 × 10^7 e.m.u. per gram.https://authors.library.caltech.edu/records/4qt0a-sxn94