Series Spectra

Robert Campbell Norman

Description

Whilst the greatest effort has been made to ensure the quality of this text, due to the historical nature of this content, in some rare cases there may be minor issues with legibility. The extent of each monograph corresponds roughly to that of a chapter of the book. Accordingly, in order that there may be continuity between the book and its supplements, the monographs are called chapters and numbered consecutively with the chapters of the book. Chapters I - XIV are in the book; subsequent chapters are monographs. References from one part of the work to another are made by chapter and page numbers. Although the form of the book, and probably much of its authorship, will be changed, its purpose will remain unaltered. It is still intended, not for experts, but for students who, having taken the usual examination courses, wish to get into touch with research. It aims at giving them such knowledge of the chief regions in which research is active that they may proceed at once to the original memoirs; much more attention is therefore given to the clear exposition of the main ideas which inspire the research, than to detailed statements of the results that have been obtained from it. References to original literature are not given; for, if the book attains its object, the literature to which it is most important that the reader should turn is that which is not yet published.

Sujets

• Sciences et techniques

Informations

• Publié par: Forgotten Books
• Date de parution: 27 novembre 2019
• Nombre de lectures: 0
• EAN13: 9780243636617
• Langue: English
• Poids de l'ouvrage: 3 Mo

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P R E E is thefiintended to suppleof monographs rst of a series ent and eventually rep ace b k on Progress in the science is rapid that it is i possibl e to make the book always j ustify its title by issuing new edition s It is pr posed therefore to issue as soon as possible a series of ono graphs similar to this dealing with th e most i portant advances in physics since the last edition and to continu e the series w henever the need arises hen the present edition the b ok is exhausted th se parts of it which can still be described as modern will be w itten and will for other no raphs of the series The extent of each nogr ph corresponds roughly to that of a chapter of the book ccordingly in order that there may be continui y between the book and its supple e ts the onographs are called chapters and nu bered c nsecutively with the chapters of the book Chapters are in the book subsequent chapters are onographs eferences from one part of the work to another are ade by chapter and page nu bers lthough the for of the book and probably uch of its authorship will be changed its purpose will remain unaltered It is still intended not experts but students having taken the usual exa ination courses wish to get into touch with research It ai s at giving the such kn wledge of the chief regions in which research is active that th ey proceed at once to the original emoirs uch m ore attention is therefore given to the clear exposition of the ain ideas which inspire the research than to detailed statements of the results that have been obtained fro it eferences to riginal literature are not given for if the b ok attains its bj ect the literature to which it is ost i portant that the reader should turn is that which is not yet published The choice of S eries S subj ect of thepectra the first ono g aph needs no j stifiwork which cation The Bohr sis based on the ry is undoubtedly the ost i po tant advance in pure physics si ce That theory will characterise an era as distinct as those

vi P RE FA E which followed the electro agnetic theory of light or the electron theory It is already inflscu encing so wide a range i ence that it has been diffiitscult to compress this monograph within the li assigned to it and th e difficulty is increased because the i mens accumulati n of facts correlated by it are not given in ordinary text books and th r ughly fa iliar the students who the work is intended owever since the f cts concerning p ical spectra other than those hydr gen heliu are not yet brought co pletely within the the ry it was decided that a brief mention the w uld suffitheo ybearing the in the ce g on the constitution of ato s and olecules is reserved for a later onograph the facts c ncerning ray spec ra ther books notably that the Braggs are available It will be obvious that in writing the monograph uch help has been obtained from S erfeld s though for the sake of variety have diverged as widely as possible from that ad irable treatise in all atters of detailed treatm ent

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t t very element in th e gaseous state possesses a characteristic spectru which appears under low dispersion as a finarr w co pared ber of bright lines that are very th enite nu dark s aces b etween the U nder higher dispersion th e lines are usually f und to be co plex and consist of a nu ber of which the breadth is c parable with the distance between the if s e of the co ponents are very cl se to and faint co red with others they are called satellites of the brighter co p nents The distinction between a line a co ponent a satellite is erely one degree but it is practically useful the word line will ften be used to include all the c ponents and satellites which are ch nearer to each ther than they are the rest of th e s ectru the wa e length such a co plex line is the ave length which would be easured with a dispersion s all separate the co ponents I a stage is alwaysis continually increased f the dispersion reached which f rther increa e reveals further c ponents But this ulti ate stage the co p nents are always f und to have afiver some s all range of wave nite breadth and to c engths This breadth is h wever characteristic of th e individual ato s that are the ctual e itters of the spectru It is due two ain causes First the at s are always in otion with dif erent velo cities and in di ferent directions relative to the bserver in virtu e the D light fr the receivedppler effect frequency the by the observer is changed in dif erent degrees S at second the are di erently situated with respect to th e f rces exerted by th eir neighbours and these f rces change the frequency slightly fr th t which would be emitted if the ato s were very distant from each other the extent this change ncrea es with the density the e itting substance whereas the D ppler change wit itsincrea es T