scholarly journals III. A critical study of spectral series.— Part I. The alkalies H and He

1911 ◽  
Vol 210 (459-470) ◽  
pp. 57-111 ◽  
Keyword(s):  
Principal Series ◽  
Atomic Weight ◽  
Spectral Lines ◽  
Critical Study ◽  
Spectral Series ◽  
Observational Error ◽  
Present Communication ◽  
Present Purpose

The following investigation was commenced some years ago, at a time when the discussion as to the atomic weight of Radium raised the question as to the dependence on their atomic weights of the wave-lengths of corresponding spectral lines of different elements of the same group. The arguments were necessarily vague and unconvincing in the absence of any exact knowledge as to the connection of wave­-length with atomic weight, even supposing such connection existed. Our knowledge of series spectra is chiefly—one might say almost wholly—due to the sets of very exact measurements of Kayser and Runge, and of Runge and Paschen, supplemented by extensions to longer and shorter wave-lengths by Bergmann, Konen and Hagenbach, Lehmann, Ram age, and Saunders. These have been only quite recently added to by Paschen and by the remarkable extension of the Sodium Principal series up to 48 terms by Wood. A most valuable feature of Kayser’s work was the publication of possible errors of observation. This has rendered it possible to test with certainty whether any relation suggesting itself is true within limits of observational error or not. In fact, without this, the investigation, of which the present communication forms a first part, could not have been carried out. So far as the author knows, Saunders is the only other observer who has accompanied his observations with estimates of this kind. Others have given probable errors—practically estimates of the exactness with which they can repeat readings of that feature of a line which they take to be the centre—an estimate of little value for the present purpose. In deducing data from a set of lines it is thus possible to express their errors in terms of the original errors in the observations, and limits to the latter give limiting variations to the former. We therefore know with certainty what latitude in inferences is permissible, and are often enabled to say that such inference is not justifiable.

VIII. A critical study of spectral series.— Part III. The atomic weight term and its import in the constitution of spectra

1914 ◽  
Vol 213 (497-508) ◽  
pp. 323-420
Keyword(s):  
Periodic Table ◽  
Principal Series ◽  
Atomic Weight ◽  
The Other ◽  
Critical Study ◽  
Spectral Series ◽  
Present Communication ◽  
The Real ◽  
Real Relation ◽  
The One

The doublet and triplet separations in the spectra of elements are, as has long been known, roughly proportional to the squares of their atomic weights, at least whenelements of the same group of the periodic table are compared. In the formulæ which give the series lines these separations arise by certain terms being deducted from the denominator of the typical sequences. For instance, in the alkalies if the p -sequence be written N/D m 2 , where D m = m +μ+α/ m the p -sequence for the second principal series has denominator D—Δ, and we get converging doublets; whereas the constant separations for the S and D series are formed by taking S 1 (∞) = D 1 (∞) = N/D 1 2 and S 2 (∞) = D 2 (∞)= N/(D 1 —Δ) 2 . It is clear that the values of Δ for the various elements will also be roughly proportional to the squares of the atomic weights. For this reason it is convenient to refer to them as the atomic weight terms. We shall denote them by Δ in the case of doublets and Δ 1 and Δ 2 in the case of triplets, using v as before to denote the separations. Two questions naturally arise. On the one hand what is the real relation between them and the atomic weights, and on the other what relation have they to the constitution of the spectra themselves ? The present communication is an attempt to throw some light on both these problems.

scholarly journals A critical study of spectral series. Part III.—The atomic weight term and its import in the constitution of spectra

1913 ◽  
Vol 89 (608) ◽  
pp. 125-127
Keyword(s):  
Periodic Table ◽  
Atomic Weight ◽  
Frequent Occurrence ◽  
Fundamental Importance ◽  
Critical Study ◽  
Spectral Series ◽  
Present Communication ◽  
Wave Numbers ◽  
Actual Relation ◽  
Universal Application

The wave numbers of the lines in a spectrum which form any of the recognised series can be calculated, as is well known, from an expression of the form n = N/D 1 2 — N/D m 2 , where N = 109675 and D m = m + fraction, the fraction being in general a function of the integer m . The constant doublet or triplet separations of S and D series are formed by the deduction of a quantity Δ, or Δ 1 , Δ 2 , in the case of triplets, from D 1 , and it has long been known that these quantities are very roughly proportional to the squares of the atomic weights when elements in the same group are compared. The present communication deals with the actual relation between Δ and the atomic weight, and with the part it plays in the general constitution of spectra. It is shown that there is a definite quantity in connection with each element which is of fundamental importance in the building up of its spectrum. It is proportional to the square of the atomic weight: in fact, if w denote the atomic weight divided by 100 its value is (90·4725 ± 0·013) w 3 . This quantity is of such universal application that it is useful to have a special name for it, and it has been called the oun ( wv ). Its value is denoted by δ 1 , but δ is used for the multiple 4δ 1 , as it is of very frequent occurrence. The evidence for its existence is based on the arc spectra of He, the elements of the Groups I and II, the Al sub-group and Sc of III and the O, S, Se of VI of the Periodic Table—in other words, all those elements in which the series lines have been allocated. It is found:— (1) That the Δ which give the doublet and triplet separations are all multiples of their respective ouns.

scholarly journals A critical study of spectral series. Part I. - The alkalies, H and He

1910 ◽  
Vol 83 (561) ◽  
pp. 226-228 ◽  
Keyword(s):  
Critical Study ◽  
Spectral Series ◽  
Present Communication ◽  
Wave Numbers ◽  
Observational Errors ◽  
Insight Into

It is generally recognised that one of the most hopeful means of gaining an insight into the structure of the atom is study of the spectra of the elements, and at present especially of the series spectra. Before, however, it is possible it is necessary to have a more definite knowledge of the relationships between the various series of the same element, and corresponding series in different elements. With this end in view, the author began some years ago a systematic discussion of the data accumulated, using for this purpose the estimated errors of observation on these spectra. These possible errors give limits of possible variation for the different constants involved, and permit of safe conclusions being drawn. The present communication gives the results affecting the spectra of the alkalies, hydrogen and helium. The chief results arrived at are the following:- 1. The wave numbers of any one series can practically all be represented within observational errors by a formula based on a modification of Rydberg's form, viz.:- n = A - N/( m + μ + α/m ) 2 .

scholarly journals X. A critical study of spectral series.—Part IV. The structure of spark spectra

1918 ◽  
Vol 217 (549-560) ◽  
pp. 361-410
Keyword(s):  
Great Majority ◽  
Special Care ◽  
The Other ◽  
Critical Study ◽  
Spectral Series ◽  
Rare Gases ◽  
Present Communication ◽  
The Way

The spectrum of an element produced by the electric spark is in general fundamentally different from that produced by the arc. The latter is marked by the predominance of groups of lines forming series associated with one another, and by lines related to these series in definite ways. In the former very few series have been discovered, the lines are very much more numerous, and the great majority are weak. Both kinds vary very much according to the way in which they are produced, and this is specially the case with spectra produced by the spark. Even when they are produced by similar methods by different observers—as, for instance, by Eder and Valenta, and by Exner and Haschek—there will be found a large number in one not included in the other and vice versâ . It is even questionable whether it is possible to draw a distinct and definite line of demarcation between the two, e. g ., in the cases of Cu and Ba, to take two instances; the arc spectra—with very numerous lines—in many respects have analogies with those of the spark. But very little is known as to the structure of the latter, beyond the fact that in some of them sets of lines with the same frequency differences are met with. The present communication is an attempt to throw some light on this question. The material at disposal is so vast that it is necessary to limit the discussion to a few elements, and even in them to restrict it to certain relations only. The elements selected are silver and gold. It had originally been intended to include also copper and barium as illustrating the transition from one to the other kind of spectra. But their inclusion would have rendered the present communication unduly long, whilst their omission enables us to confine the discussion to the elaboration of a single principle. The reason for the selection is that the author has had occasion to study with special care for other purposes the spectra of Ag and Ba, whilst those of Au and Cu—belonging to the same group as Ag—were specially investigated to see if the results afforded by Ag were supported by them. That of Cu was also interesting, as in the arc there are a very large number of doublets and triplets discovered by Rydberg; indeed the origins of some of the frequency differences observed were first suggested by the case of Cu in which their values are comparatively small. But it required the support of the larger values afforded by Ag and Au to firmly establish the relations. Similar relations have been found in many other elements. The spectra of the rare gases from Ne to RaEm are built on a precisely similar plan, and in fact a map for some of the Kr lines was drawn many years ago on the plan of those given here for Ag and Au, although at that time the origin of the differences was not known.

scholarly journals II. A critical study of spectral series.–Part II. The p and s sequences and the atomic volume term

1913 ◽  
Vol 212 (484-496) ◽  
pp. 33-73 ◽  
Keyword(s):  
Atomic Weight ◽  
Atomic Volume ◽  
Critical Study ◽  
Present Communication ◽  
High Melting Point ◽  
Small Intensity ◽  
Complete Discussion ◽  
Ordinary Type ◽  
The Comparative Study ◽  
Made In

The present communication is in continuation of one presented to the Society in 1909. The greater part of the work was completed at that time, and it was hoped that it would be published shortly afterwards. Certain points, however, arose which the author was anxious to settle, and this led to a consideration of a number of spectra in which series of the ordinary type had not yet been recognised. He hopes to deal with some of the most interesting points which have come to light in the course of that consideration, chiefly connected with the atomic weight term, and the constitution of certain spectra, in an ensuing paper. In the present one the constitutions of the sequences on which the Principal and Sharp series depend, and their relation to the atomic volume of the element, which were brought to light in Part I., are further considered in connection with the spectra of the second and third groups of elements. It was hoped to have included in the third group the high melting-point sub-group Sc, Y, La, Yb, and considerable progress had been made in reducing their spectra. They all show doublet series of S and D types, but their complete consideration would have taken so much time, better devoted to the general constitutional points which had arisen, that it was decided to postpone it. The evident importance, however, of the comparative study of all the elements in the same group of the periodic system made it seem desirable to give some attention to those elements which might possibly fill the gaps. It is generally acknowledged that these belong probably to elements associated with the rare earths, and their atomic weights give some indication of the places they should fill. Their spectra consist of a multitude of lines chiefly of medium or small intensity, and their complete discussion involves a great deal of time and close attention. All those, however, which the author has so far investigated show more or less analogous relationships, intimately connected, and irresistibly suggesting the débris , so to say, of strong lines. The connection is based on certain properties of the atomic weight term referred to above. The evidence of the spectrum of Eu leaves little doubt but that it fills the vacant space between Cd and Hg. Probably the gap between In and Tl is occupied by Gd. A superficial consideration of the spectrum of the latter shows a large number of doublets with a separation of 5000. This number agrees with its atomic weight and its position between In (2212) and T1 (7792). As is well known, the spectrum of Ra is quite analogous to those of the Ca group, whilst possibly the gap between it and Ba may be filled by another radio-active substance. An attempt has been made to allot the S and D series of Eu and Ba and the result is given in Appendix I. In response to suggestions made to me in respect of Part I., I have ventured to give in a second appendix lists of the S and P series lines of the elements considered in the present communication. The type of formula used here and in Part I. has been employed by Mogendorff in a still earlier paper read before the Royal Society of Amsterdam in November, 1906. He there showed that the formula reproduces the lines of Li, Na, Zn, and Tl in the different series with great exactness, and stated that he had also obtained corresponding formulæ for other elements.

scholarly journals Stark Width Regularities within Neutral Calcium Spectral Series

2012 ◽  
Vol 29 (1) ◽  
pp. 20-28 ◽  
Author(s):  
I. Tapalaga ◽  
I. P. Dojčinović ◽  
M. K. Milosavljević ◽  
J. Purić
Keyword(s):  
Term Structure ◽  
Low Temperatures ◽  
Spectral Lines ◽  
Spectral Series ◽  
Stark Broadening ◽  
Proton Impact ◽  
Transition Level ◽  
Lower Transition ◽  
Upper Level ◽  
Stark Width

AbstractDependences of electron and proton impact Stark width on the upper level ionization potential within different series of the neutral calcium spectral lines have been evaluated and discussed. The similar dependences previously found for the electron impact contribution were also obtained for the proton impact contribution to the Stark broadening. The emphasis is on the term structure influence on the studied Stark width dependences. The influence of the lower transition level and transition term is higher at low temperatures. After establishing these dependences, predictions were made for Stark widths of neutral calcium spectral lines not measured experimentally or calculated theoretically until now.

scholarly journals Dispersion of light by Potassium Vapour

1910 ◽  
Vol 84 (570) ◽  
pp. 209-225 ◽  
Keyword(s):  
Wave Length ◽  
Principal Series ◽  
Visible Spectrum ◽  
Ultra Violet ◽  
Anomalous Dispersion ◽  
Present Communication ◽  
Absorption Region ◽  
Sodium Potassium ◽  
Light Passing ◽  
Quantitative Results

Anomalous dispersion in the region of the red lines of potassium was first observed by Ebert in 1904. The method adopted for Ebert’s experiments was a modified form of the crossed prism method used by Wood in the investigation of the corresponding phenomena in the case of sodium. Potassium was heated in a tube through which two currents of hydrogen passed from each end to a central outlet. The cool hydrogen kept the potassium vapour in a prismatic form, so that light passing along the length of the tube suffered deviation and dispersion by the potassium vapour prism. The author of the present communication has shown that there is no need for the hydrogen streams. If the tube be kept cool on its upper surface the metallic vapour takes of itself a prismatic form or is arranged in layers of decreasing density, and so behaves in a similar way to a prism of homogeneous vapour. The present communication deals with quantitative results from the measurement of dispersions at different wave-lengths, and it appears that the deviation due to potassium vapour is observable over the whole of the visible spectrum and for a considerable distance in the ultra-violet. Strong absorption takes place at the lines of the principal series and for wave-lengths near these series lines we have "anomalous" dispersion. This phenomenon has been observed at seven of the pairs forming the principal series lines for potassium—as the pairs of lines in this series get closer and closer together with diminishing wave-length, the dispersion effects after the first two pairs are only observable outside the lines forming a pair, but there appears a lack of symmetry in the observed dispersion curves corresponding to the different intensities of the lines forming the pair. The dispersion to be observed may then be regarded as that corresponding to the principal series absorption lines; no other absorption region seems to affect the dispersion —at any rate at low densities of vapour.

scholarly journals XXI. Experimental researches on atomic weights

1833 ◽  
Vol 123 ◽  
pp. 523-544 ◽  
Keyword(s):  
First Principles ◽  
Atomic Weight ◽  
Point Of View ◽  
Relative Accuracy ◽  
The Other ◽  
Present Communication ◽  
Present Essay ◽  
The Subject ◽  
Important Object ◽  
Experimental Researches

The present communication may be viewed as the continuation of an Essay on the Composition of the Chloride of Barium, which was honoured with a place in the Philosophical Transactions for the year 1829. In resuming the subject after such a long interval, I feel it right to apologize to the Society for the unfinished state in which that Essay has hitherto been left,—an omission far from voluntary, and entirely due to circumstances not subject to my own controul. In one point of view, however, the delay has been advantageous: it has afforded an opportunity to chemists to verify or correct the results contained in my first Essay, and has enabled me to repeat and extend my researches. The object which I proposed to myself in commencing the present inquiry, was to re-examine some of those estimates which chemists have occasion to use continually as elements in their calculations, and to confide in as the foundation of their doctrines. With this view I undertook to determine the relative accuracy of the atomic weights which the British and Continental chemists respectively employ; and several circumstances induced me to begin by analysing the chloride of barium. Dr. Thomson, on whose experiments the British chemists relied, had obtained so many of his results by means of the chloride of barium, that any material error in the constitution of that compound would necessarily vitiate a large part of his table of equivalents; and if, on the other hand, the estimate of Dr. Thomson proved to be correct, an important error would be chargeable against Berzelius, whose numbers are very generally adopted on the Continent. The result of the inquiry is now well known: the source of fallacy, pointed out in my first communication, has been admitted by Dr. Thomson in the new edition of his System of Chemistry, and he has accordingly changed the equivalent of barium from 70 to 68. The inevitable consequence of this change must be apparent to every one who is acquainted with the method of analysis so frequently resorted to by Dr. Thomson. Many of the experiments described in his First Principles of Chemistry are now at irreconcilable variance with each other, and, if relied upon at all, subvert the conclusions which they once appeared to establish. Nor can those parts of his work which are not subject to this criticism be safely applied to the purposes of science. His view, for instance, of the composition of the compounds of oxygen with phosphorus, arsenic, and antimony, has been lately abandoned by himself; and in the course of the present Essay I shall have occasion to prove, that the atomic weights which he has employed for silver and chlorine are likewise inadmissible. His analysis of sulphate of zinc, which was made, to use Dr. Thomson’s own words, “the foundation on which he endeavoured to rear the whole subsequent doctrine of the atomic weight of bodies,” is peculiarly objectionable. Besides being vitiated by his error in the equivalent of barium, the oxide of zinc was determined by a method which involved an error in principle, and was in practice so complex as to be unfit for the extremely important object which it was intended to serve.

scholarly journals Wave-lengths of additional lines in the many-lined spectrum of hydrogen

1925 ◽  
Vol 108 (748) ◽  
pp. 592-606 ◽  
Keyword(s):  
Current Density ◽  
Present Author ◽  
Spectral Lines ◽  
Vacuum Tube ◽  
Narrow Capillary ◽  
Present Purpose ◽  
The Many ◽  
Concave Grating ◽  
Accurate Wave

During the investigation of the secondary spectrum lines of hydrogen, in which Prof. Richardson and the present author have been recently engaged, we found many weak lines which are not recorded in any published tables. Most of them were found on the two spectrum plates taken by Prof. Merton and lent to us, as well as on our plates taken under quite different conditions from the above. Because our investigation was partly to find the regularity of the spectrum, it was thought highly desirable to know the accurate wave-lengths of these weak lines. On the above-mentioned plates of Prof. Merton, which were taken with an Anderson concave grating, the spectral lines were much better resolved than on our plates. They were also rather over-exposed, and therefore quite suitable to the present purpose. For these reasons the following measurements were entirely made with those plates. It should be added that these two plates were taken by Prof. Merton with a vacuum tube having a narrow capillary, and the current density must have been at least twenty-five times as great as in the tubes which Merton and Barratt used for measuring the lines given in their tables. There is little doubt that this and perhaps other differences in the conditions of excitation is the reason why the additional lines which I have measured were not observed by Merton and Barratt on the plates they used for measurement.

scholarly journals Stark broadening of B I spectral lines within 2s22p - 2s2nd Spectral Series

2020 ◽  
Vol 50 (1) ◽  
Author(s):  
M. Christova ◽  
M.S. Dimitrijević ◽  
S. Sahal-Bréchot
Keyword(s):  
Spectral Lines ◽  
Spectral Series ◽  
Stark Broadening
Sign in / Sign up

Export Citation Format

Share Document