It is now just 50 years since Eddington's first paper on Cepheid pulsation (1). He recognized immediately the central problem of the maintenance of pulsation and proceeded to develop (2) the linear theory leading to the period-density relation. He continued to devote considerable attention (3) to understanding the physical mechanisms responsible for exciting pulsation and recognized all of the essential aspects of that problem.
\n\nHis point of view on pulsation was expressed in Stars and Atoms: 'to be able to see the machinery of a star throbbing with activity is most instructive for the development of our knowledge'. This view constitutes the theme of the work I will discuss here on the application of non-linear methods to the Cepheid variables.
\n\nThe discussion will be divided into three main parts, of which the first will be devoted to the methods of investigation. The second part will be aimed at understanding the physical causes of pulsation and the mechanism of amplitude limitation. The third part will discuss the various results of pulsation calculations. The objective of this part will be to find ways by which all the significant physical parameters (mass M, mean effective temperature Te05, mean luminosity L05, and helium mass fraction Y) that control pulsation can be deduced from observation of the variable star.
", "issn": "0035-8738", "publisher": "Royal Astronomical Society", "publication": "Quarterly Journal of the Royal Astronomical Society", "publication_date": "1968", "series_number": "1", "volume": "9", "issue": "1", "pages": "13-39" }, { "id": "authors:nt0s9-9zh73", "collection": "authors", "collection_id": "nt0s9-9zh73", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120905-154809533", "type": "article", "title": "Pulsation Theory", "author": [ { "family_name": "Christy", "given_name": "R. F.", "clpid": "Christy-R-F" } ], "abstract": "This review will concentrate on the question of pulsation in what we will\ncall the Cepheid instability strip in the H-R diagram or in the log g-log T_0\ndiagram. This strip includes, of course, the classical \u03b4 Cephei variables, the\nPopulation II Cepheids, and the RR Lyrae variables. In addition to these, it\nappears that the RV Tauri variables, \u03b4 Scuti variables, and dwarf Cepheids\nall belong in this same general class. Clearly excluded from this class are the \u03b2 Cephei variables, the Mira variables, and other types of red variables. For a\nmore extensive discussion, the review of Ledoux & Walraven (1) is recommended.", "doi": "10.1146/annurev.aa.04.090166.002033", "issn": "0066-4146", "publisher": "Annual Reviews", "publication": "Annual Review of Astronomy and Astrophysics", "publication_date": "1966-09", "volume": "4", "pages": "353-392" }, { "id": "authors:ecxxv-y1a55", "collection": "authors", "collection_id": "ecxxv-y1a55", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20121005-144827779", "type": "article", "title": "A Study of Pulsation in RR Lyrae Models", "author": [ { "family_name": "Christy", "given_name": "Robert F.", "clpid": "Christy-R-F" } ], "abstract": "Non-linear calculations of intermediate amplitude to investigate stability have been carried out for one hundred RR Lyrae models of varying composition, mass, luminosity, and effective temperature. Of these, the calculations have been extended to the maximum amplitude for fifty models. The dependence of the location of the instability strip on composition, mass, and luminosity has been explored. In particular, the high-temperature boundary of the strip increases by 500\u00b0 K for each 15 per cent increase in the mass fraction of helium.
\n\nThe dependence on effective temperature of the phase shift, the ratio of radius and luminosity amplitudes, and the shape of the light-curve has been explored, and the correlations of these three measures have been found. These measures may then be applied to observed variables to determine their location in the instability strip and the helium content of their envelopes. The examples studied give best agreement at about 30 per cent helium by mass.
\n\nThe calculations reveal many details of the shapes of the light- and velocity-curves which may be compared to observation. A number of features of these curves of known variables are discussed, and the underlying explanation is investigated.
\n\nThe sources of the driving energy of these models have been explored. In the models of the most favored composition, 30 per cent helium, the hydrogen ionization region is almost as important to the driving as is the He II ionization. The effects that cause the amplitude to cease growing and level off at the observed maximum amplitude are explored: they appear to involve several non-linear effects, particularly a steep velocity front, in the He II ionization zone.
\n\nA new kind of period-luminosity relation has been discovered. The shortest period at which the fundamental mode persists, before it changes to the first harmonic, has been found to be independent of mass and composition and to depend only on the luminosity. This relation was found to be Ptr = 0 057 (L/L\u2609)0.6 days. This has been used to interpret the varying period distributions of RR Lyrae stars in clusters and in the field with the result that the luminosities are found to vary from Mbol = 0.57 for very metal-weak clusters to Mbol = 0.96 for clusters only slightly weak in metals. Metal-rich variables are slightly less luminous still. These results lead to the conclusion that the masses of RR Lyrae stars are near 0.5 M\u2609, which must imply a significant mass loss. These conclusions appear to be consistent with the possible interior models.
", "doi": "10.1086/148593", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "1966-04", "series_number": "1", "volume": "144", "issue": "1", "pages": "108-179" }, { "id": "authors:17kty-hab61", "collection": "authors", "collection_id": "17kty-hab61", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20121005-161718496", "type": "article", "title": "A Model Of W Virginis With Rv Tauri Characteristics : Notes", "author": [ { "family_name": "Christy", "given_name": "R. F.", "clpid": "Christy-R-F" } ], "abstract": "N/A", "doi": "10.1086/148766", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "1966", "series_number": "1", "volume": "145", "issue": "1", "pages": "337-339" }, { "id": "authors:cjsx3-z9667", "collection": "authors", "collection_id": "cjsx3-z9667", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120814-105255582", "type": "article", "title": "The Calculation of Stellar Pulsation", "author": [ { "family_name": "Christy", "given_name": "Robert F.", "clpid": "Christy-R-F" } ], "abstract": "In this paper we report methods of computation\nwhich have been developed to provide a theoretical\nunderstanding of the RR Lyrae and Cepheid type\npulsating stars. The results reported are intended to\nilluminate the methods of calculation and to provide\ninsight into the physical processes in these stars. A\nsurvey of pulsation in RR Lyrae models using\nthese methods has also been carried out and will be\nreported soon in another journal. A survey of pulsation\nin Cepheid models has been initiated and will be\ncontinued.", "doi": "10.1103/RevModPhys.36.555", "issn": "0034-6861", "publisher": "American Physical Society", "publication": "Reviews of Modern Physics", "publication_date": "1964-04", "series_number": "2", "volume": "36", "issue": "2", "pages": "555-571" }, { "id": "authors:3wb0g-bx385", "collection": "authors", "collection_id": "3wb0g-bx385", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20121005-154448925", "type": "article", "title": "\u03b3 rays from an extranuclear direct capture process", "author": [ { "family_name": "Christy", "given_name": "Robert F.", "clpid": "Christy-R-F" }, { "family_name": "Duck", "given_name": "Ian", "clpid": "Duck-I" } ], "abstract": "Direct electric dipole capture \u03b3-ray transitions are calculated for a numbers of cases of charged particle capture in nuclei. It is found that when the \u03b3-ray energy is sufficiently low \u2014 below about 2 MeV \u2014 the capture matrix element is determined by regions external to the usual \"nuclear radius\". A number of cases of this type are discussed and the calculations compared with experiment. The calculations are extended to the keV region in those cases when the process is of astrophysical interest.", "doi": "10.1016/0029-5582(61)91019-7", "issn": "0029-5582", "publisher": "Elsevier", "publication": "Nuclear Physics", "publication_date": "1961", "series_number": "1", "volume": "24", "issue": "1", "pages": "89-101" }, { "id": "authors:jsyek-p3t91", "collection": "authors", "collection_id": "jsyek-p3t91", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BURpr56", "type": "article", "title": "Californium-254 and Supernovae", "author": [ { "family_name": "Burbidge", "given_name": "G. R.", "clpid": "Burbidge-G-R" }, { "family_name": "Hoyle", "given_name": "F.", "clpid": "Hoyle-Fred" }, { "family_name": "Burbidge", "given_name": "E. M.", "clpid": "Burbidge-E-M" }, { "family_name": "Christy", "given_name": "R. F.", "clpid": "Christy-R-F" }, { "family_name": "Fowler", "given_name": "W. A.", "clpid": "Fowler-W-A" } ], "abstract": "It is suggested that the spontaneous fission of Cf254 with a half-life of 55 days is responsible for the form of the decay light-curves of supernovae of Type I which have an exponential form with a half-life of 55 nights. The way in which Cf254 may be synthesized in a supernova outburst, and reasons why the energy released by its decay may dominate all others are discussed. The presence of Tc in red giant stars and of Cf in Type I supernovae appears to be observational evidence that neutron capture processes on both a slow and a fast time-scale have been necessary to synthesize the heavy elements in their observed cosmic abundances.", "doi": "10.1103/PhysRev.103.1145", "issn": "0031-899X", "publisher": "American Physical Society", "publication": "Physical Review", "publication_date": "1956-09-01", "series_number": "5", "volume": "103", "issue": "5", "pages": "1145-1149" }, { "id": "authors:y3b3t-32268", "collection": "authors", "collection_id": "y3b3t-32268", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20121005-163952917", "type": "article", "title": "Supernovae and Californium 254", "author": [ { "family_name": "Baade", "given_name": "W.", "clpid": "Baade-W" }, { "family_name": "Burbidge", "given_name": "G. R.", "clpid": "Burbidge-G-R" }, { "family_name": "Hoyle", "given_name": "F.", "clpid": "Hoyle-Fred" }, { "family_name": "Burbidge", "given_name": "E. M.", "clpid": "Burbidge-E-M" }, { "family_name": "Christy", "given_name": "R. F.", "clpid": "Christy-R-F" }, { "family_name": "Fowler", "given_name": "W. A.", "clpid": "Fowler-W-A" } ], "abstract": "[No abstract]", "issn": "0004-6280", "publisher": "Astronomical Society of the Pacific", "publication": "Publications of the Astronomical Society of the Pacific", "publication_date": "1956-08", "series_number": "403", "volume": "68", "issue": "403", "pages": "296-300" }, { "id": "authors:03574-vb893", "collection": "authors", "collection_id": "03574-vb893", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:SHEpr54b", "type": "article", "title": "Coulomb Excitation of F19 by Alpha Particles", "author": [ { "family_name": "Sherr", "given_name": "R.", "clpid": "Sherr-R" }, { "family_name": "Li", "given_name": "C. W.", "orcid": "0000-0002-0758-5334", "clpid": "Li-Chen-W" }, { "family_name": "Christy", "given_name": "R. F.", "clpid": "Christy-R-F" } ], "abstract": "Gamma rays emitted in the excitation of F19 by \u03b1 particles of 0.6 to 2.8 Mev have been studied. Resonances are found in the reaction F19(\u03b1, p)Ne22* at \u03b1 particle energies greater than 1.3 Mev and in the inelastic excitation of 109-kev and 196-kev levels in F19 at energies greater than 2.2 Mev. At bombarding energies below 2 Mev, the cross sections for inelastic excitation of F19 decrease much too slowly for compound nucleus formation and are identified as being due to Coulomb excitation. The observed cross sections in the region 0.6 Mev to 2 Mev agree well with the theory for Coulomb excitation. The electromagnetic transition probabilities for decay of these states deduced from the excitation cross sections are in good agreement with those found from direct measurement of the lifetimes by Thirion, Barnes, and Lauritsen. Together with the results of Peterson, Barnes, Fowler, and Lauritsen on the inelastic excitation of fluorine by protons, these experiments lead to spin and parity assignment of \u00bd- for the 109 kev state and 5/2+ for the 196-kev state of F19. The observed angular distributions of the \u03b3 rays from Coulomb excitation by \u03b1 particles are also in accord with theory.", "doi": "10.1103/PhysRev.96.1258", "issn": "0031-899X", "publisher": "Physical Review", "publication": "Physical Review", "publication_date": "1954-12-01", "series_number": "5", "volume": "96", "issue": "5", "pages": "1258-1266" }, { "id": "authors:qhcjx-vfx19", "collection": "authors", "collection_id": "qhcjx-vfx19", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:SHEpr54a", "type": "article", "title": "Low Excited States of F19. III. Coulomb Excitation by \u03b1 Particles", "author": [ { "family_name": "Sherr", "given_name": "R.", "clpid": "Sherr-R" }, { "family_name": "Li", "given_name": "C. W.", "orcid": "0000-0002-0758-5334", "clpid": "Li-Chen-W" }, { "family_name": "Christy", "given_name": "R. F.", "clpid": "Christy-R-F" } ], "abstract": "We have investigated the yield of gamma rays resulting from the bombardment of F19 by \u03b1 particles [1]. Up to an \u03b1-particle energy 2.8 Mev we observed only the 1.28 Mev \u03b3 ray of the reaction F19(\u03b1,p)Ne22*, and the 114-kev and 200-kev radiations from the first and second excited states of F19 produced by inelastic scattering of the \u03b1 particles. The \u03b3 rays were detected with a 1 1/2 in. X 1 1/2 in. sodium iodide scintillation spectrometer. The pulse spectrum was recorded with a 10-channel analyzer.", "doi": "10.1103/PhysRev.94.1076.2", "issn": "0031-899X", "publisher": "Physical Review", "publication": "Physical Review", "publication_date": "1954-05-15", "series_number": "4", "volume": "94", "issue": "4", "pages": "1076-1077" }, { "id": "authors:zb56t-2xq24", "collection": "authors", "collection_id": "zb56t-2xq24", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CHRpr54", "type": "article", "title": "Low Excited States of F19. IV. Angular Distributions", "author": [ { "family_name": "Christy", "given_name": "R. F.", "clpid": "Christy-R-F" } ], "abstract": "The angular distributions [1] of inelastically scattered protons and the subsequent \u03b3 rays at resonances in Ne20 afford one means of establishing properties of low excited states of F19. For this purpose the 2- resonances in Ne20 made by p-wave protons on F19 in channel spin 1 are most suitable and are discussed below. Since it was not possible to measure the inelastically scattered protons leading to the 114-kev state at these resonances, we discuss only the angular distribution of protons leading to the 200-kev state and of the two \u03b3 rays.", "doi": "10.1103/PhysRev.94.1077", "issn": "0031-899X", "publisher": "Physical Review", "publication": "Physical Review", "publication_date": "1954-05-15", "series_number": "4", "volume": "94", "issue": "4", "pages": "1077-1078" }, { "id": "authors:88hxn-2p079", "collection": "authors", "collection_id": "88hxn-2p079", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CHRpr53", "type": "article", "title": "The Coupling of Angular Momenta in Nuclear Reactions", "author": [ { "family_name": "Christy", "given_name": "R. F.", "clpid": "Christy-R-F" } ], "abstract": "Seven nuclear reactions have been examined where the angular distribution of reaction products depends on the type of coupling of angular momentum vectors in the nucleus. In six of the seven, the experimental angular distribution is consistent with the assumption of Russell-Saunders coupling in the nucleus. In three of the seven, the experiments are consistent with the assumption that the bombarding particle brings a definite j in the reaction. Neither assumption is sufficient to explain the result in one reaction (B11+P).", "doi": "10.1103/PhysRev.89.839", "issn": "0031-899X", "publisher": "Physical Review", "publication": "Physical Review", "publication_date": "1953-02-15", "series_number": "4", "volume": "89", "issue": "4", "pages": "839-842" }, { "id": "authors:vp90h-d2880", "collection": "authors", "collection_id": "vp90h-d2880", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CHRrmp48", "type": "article", "title": "Proton Widths of Light Nuclei", "author": [ { "family_name": "Christy", "given_name": "R. F.", "clpid": "Christy-R-F" }, { "family_name": "Latter", "given_name": "R.", "clpid": "Latter-R" } ], "abstract": "When evaluating resonances in nuclear reactions involving charged particles, it is convenient to separate from the observed widths the known energy dependent factors so as to get some absolute measure of the reaction probability which can be compared for different resonances and different nuclei.", "doi": "10.1103/RevModPhys.20.185", "issn": "0034-6861", "publisher": "Reviews of Modern Physics", "publication": "Reviews of Modern Physics", "publication_date": "1948-01-01", "series_number": "1", "volume": "20", "issue": "1", "pages": "185-190" }, { "id": "authors:72hr5-x7f88", "collection": "authors", "collection_id": "72hr5-x7f88", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CHRpr47", "type": "article", "title": "The conservation of momentum in the disintegration of Li8", "author": [ { "family_name": "Christy", "given_name": "R. F.", "clpid": "Christy-R-F" }, { "family_name": "Cohen", "given_name": "E. R.", "clpid": "Cohen-E-R" }, { "family_name": "Fowler", "given_name": "W. A.", "clpid": "Fowler-W-A" }, { "family_name": "Lauritsen", "given_name": "C. C.", "clpid": "Lauritsen-C-C" }, { "family_name": "Lauritsen", "given_name": "T.", "clpid": "Lauritsen-T" } ], "abstract": "Apparatus for the introduction of radioactive materials into a cloud chamber has been employed to investigate the conservation of momentum in the \u03b2-decay of Li8 to Be8, which subsequently breaks up into two \u03b1-particles. The projection on the plane of measurement of the angle between the two \u03b1-particles is a measure of one component of the recoil momentum of the Be8. Additional information is obtainable from the momentum of the electron but relatively few cases occur where both \u03b1-particles and the electron are in the plane of the cloud chamber. The Li8 is produced by bombarding with deuterons a thin deposit of LiOH on beryllium or gold foils. The mean squares of the observed momenta relative to the maximum possible momenta were 0.247 (Be foil) and 0.349 (Au foil). Corrected for scattering and other errors these become 0.197\u00b10.025 and 0.207\u00b10.034, respectively, the probable errors quoted being statistical in origin. The weighted mean, rounded off to two figures, is 0.20\u00b10.02. This value is roughly twice that obtained taking into account only the emitted electrons, and approximately equal to that calculated for an electron and neutrino emitted with no preferred angle of ejection between them.", "doi": "10.1103/PhysRev.72.698", "issn": "0031-899X", "publisher": "Physical Review", "publication": "Physical Review", "publication_date": "1947-10-15", "series_number": "8", "volume": "72", "issue": "8", "pages": "698-711" }, { "id": "authors:07mnt-y8h13", "collection": "authors", "collection_id": "07mnt-y8h13", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CHRpr42", "type": "article", "title": "Precise Determination of the Fine Structure Constant from X-Ray Spin Doublet Splitting", "author": [ { "family_name": "Christy", "given_name": "R. F.", "clpid": "Christy-R-F" }, { "family_name": "Keller", "given_name": "J. M.", "clpid": "Keller-J-M" } ], "abstract": "Corrections to the Sommerfeld formula for the LII-LIII x-ray spin doublet splitting, to take into account departures from a pure Coulomb field for heavy elements caused by interactions between electrons, are calculated by using Dirac wave functions for a Coulomb field and calculating, with all relativistic corrections, the terms in the electron interaction of order e^2 i.e., of relative order 1/Z, compared to the Sommerfeld splitting. The result is applied to experimental data for elements varying from Z=60 to Z=92, to obtain a direct experimental value for the fine structure constant. By the method of least squares, we find 1/\u03b1=\u210fc/e^2=136.93 with an estimated limit of error of 0.18.", "doi": "10.1103/PhysRev.61.147", "issn": "0031-899X", "publisher": "Physical Review", "publication": "Physical Review", "publication_date": "1942-02-01", "series_number": "3-4", "volume": "61", "issue": "3-4", "pages": "147-152" }, { "id": "authors:kzvmt-xga67", "collection": "authors", "collection_id": "kzvmt-xga67", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CHRpr41a", "type": "article", "title": "Burst Production by Mesotrons", "author": [ { "family_name": "Christy", "given_name": "R. F.", "clpid": "Christy-R-F" }, { "family_name": "Kusaka", "given_name": "S.", "clpid": "Kusaka-Shuichi" } ], "abstract": "Assuming that, under great absorbing thicknesses, cosmic-ray bursts are cascade showers from high energy soft secondaries produced in the shielding matter by mesotron-electron collisions and by mesotron bremsstrahlung, we have calculated the frequency of burst production as a function of burst size. For the mesotron of spin 1 and moment e\u210f/2\u03bcc, we have used the previously calculated knock-on formulae, supplemented by our own calculations of the bremsstrahlung; for the latter, the cross section has terms, significant for our work, in E, ln2 E, and ln E. Up to energies close to 10^11 ev, only slight modifications are introduced by omitting altogether those processes which cannot be treated by the Born approximation, and the minimum cross sections we used differ little from those given directly by the Born approximation. Using these cross sections, the cascade theory of showers, and a modified form of the Furry model to take into account the fluctuations, the frequency of burst production was calculated. The sea-level data of Schein and Gill give for the number of bursts of size greater than S, NS\u223cS^-\u03b3, with \u03b3=1.8. Our calculations give for spin 1, \u03b3\u223c1.5 and numerically too many by a factor of 20. Similar calculations for the mesotron of spin 0 give \u03b3\u223c1.8 and the same in number as the observations within an uncertainty of about a factor 1.5. For spin \u00bd and moment e\u210f/2\u03bcc, the bursts are approximately twice as numerous as for spin 0. This evidence thus favors spin 0, or possibly spin \u00bd, but tends to exclude spin 1.", "doi": "10.1103/PhysRev.59.414", "issn": "0031-899X", "publisher": "Physical Review", "publication": "Physical Review", "publication_date": "1941-03-01", "series_number": "5", "volume": "59", "issue": "5", "pages": "414-421" }, { "id": "authors:b9cpt-rm856", "collection": "authors", "collection_id": "b9cpt-rm856", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CHRpr41b", "type": "article", "title": "The Interaction of \u03b3-Rays with Mesotrons", "author": [ { "family_name": "Christy", "given_name": "R. F.", "clpid": "Christy-R-F" }, { "family_name": "Kusaka", "given_name": "S.", "clpid": "Kusaka-Shuichi" } ], "abstract": "Differential cross sections for the production of a mesotron pair by a \u03b3-ray and for the bremsstrahlung of a mesotron in the electromagnetic field of a nucleus have been calculated. Both the Proca wave field and the Kemmer matrix formulations of the theory for mesotrons of unit spin and unit magnetic moment were used. These differential cross sections have been integrated in the limit where the energies of the mesotrons and photon are large compared to the rest energy of the mesotron. For a pure Coulomb field, the integrated cross sections are A\u03b1Z^2e^4E^2/(\u03bcc^2)^4 where for pair production A=19/72 and E is the \u03b3-ray energy, and for bremsstrahlung A=11/72 and E is the initial mesotron energy. Since in these processes the important impacts are much closer than the nuclear radius, these cross sections do not describe correctly the electromagnetic effects in the neighborhood of an actual nucleus. The cross sections in a field of the form (Ze/r)(1-e^(-r/d)) where d is the nuclear radius and is taken to be 5\u210fZ^(1/3)/6\u03bcc, are B\u2032\u03b1Z^(5/3)e^4E/(\u03bcc^2)^3 where E is defined as before and B\u2032=\u03c0/6 and \u03c0/18 for pair production and bremsstrahlung, respectively. Since considerations of the validity of the Born approximation method used show that the leading terms in the cross sections lose their validity before they become dominant, terms of lower order which give cross sections increasing only logarithmically with the energy have been calculated by the method of virtual quanta. Further, to estimate the minimum values of the cross sections beyond the range of validity, the frequency integral in the virtual quantum calculation was cut off at k/\u03bcc^2=\u210fc/e^2.", "doi": "10.1103/PhysRev.59.405", "issn": "0031-899X", "publisher": "Physical Review", "publication": "Physical Review", "publication_date": "1941-03-01", "series_number": "5", "volume": "59", "issue": "5", "pages": "405-414" }, { "id": "authors:v9mfs-gps11", "collection": "authors", "collection_id": "v9mfs-gps11", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CHRpr40", "type": "article", "title": "A Precise Determination of the Fine Structure Constant", "author": [ { "family_name": "Christy", "given_name": "R. F.", "clpid": "Christy-R-F" }, { "family_name": "Keller", "given_name": "J. M.", "clpid": "Keller-J-M" } ], "abstract": "About a year ago, R.T. Birge [1] suggested the possibility of an experimental determination of the fine structure constant based on measurements of the x-ray spin doublet splitting (LII-LIII levels). A direct determination of this quantity is of interest because of the discrepancies existing in the values of the atomic constants, and because of controversial ideas as to the value of this constant itself.", "doi": "10.1103/PhysRev.58.658", "issn": "0031-899X", "publisher": "Physical Review", "publication": "Physical Review", "publication_date": "1940-10-01", "series_number": "7", "volume": "58", "issue": "7", "pages": "658" }, { "id": "authors:m2h9g-59h27", "collection": "authors", "collection_id": "m2h9g-59h27", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:CHRpr39", "type": "article", "title": "Electric Quadrupole Moment of the Deuteron", "author": [ { "family_name": "Christy", "given_name": "R. F.", "clpid": "Christy-R-F" }, { "family_name": "Kusaka", "given_name": "S.", "clpid": "Kusaka-Shuichi" } ], "abstract": "Kellogg, Rabi, Ramsey, and Zacharias [1] have pointed out that their observations on the magnetic moments of H2, D2 and HD molecules can be accounted for if the deuteron is assumed to have an electric quadrupole moment of magnitude", "doi": "10.1103/PhysRev.55.665", "issn": "0031-899X", "publisher": "Physical Review", "publication": "Physical Review", "publication_date": "1939-04-01", "series_number": "7", "volume": "55", "issue": "7", "pages": "665" } ]