DISCOVERY OF ELECTRON WAVES It looked at this time- in the vear 1913- as if the authentic key to the spectra had at last been found, as if only time and patience would be needed to resolve their riddles completely. But this hope was never fulfilled. The first brilliant triumphs of the theory were followed by yet others, but soon the going became distressingly difficult, and finally, despite the untiring ef- forts of countless helpers, the attack came virtually to a standstill. The feeling grew that deeply as Bohr had dived he had not, so to speak, touched bottom. What was wanted, it was felt, was a new approach, a new theory of the atom which would embrace necessarily all the virtues of the Bohr theory and go beyond it-a theory which would contain some vaguely sensed unifying principle which, it was felt, the Bohr theory lacked Such an underlying principle had been sought for almost from the first By 1924 one or two ideas of promise had been put forward and were being to grow into that marvelous synthesis, the present-day quantum mechanics Louis de broglie put forward in his doctor s thesis the idea that even as light, so matter has a duality of aspects; that matter like light possesses both the properties of waves and the properties of particles. The various"restric- tions"of the Bohr theory were viewed as conditions for the formation of standing electron wave patterns within the atom Reasoning by analogy from the situation in optics and aided by the clue that Planck's constant is a necessary ingredient of the Bohr's theory, de Broglie assumed that this constant would connect also the particle and wave aspects of electrons, if the latter really existed. De Broglie assumed that, as with light, the correlation of the particle and wave properties of matter would be expressed by the relations (Energy of particle)E=hu(frequency, i.e. waves/unit time (Momentum of particle)p= lo(wave number, ie waves/unit distance) The latter may be written in the more familiar form 2=ly/p, where Arep- resents wavelength Perhaps no idea in physics has received so rapid or so intensive devel- opment as this one. De Broglie himself was in the van of this development but the chief contributions were made by the older and more experienced Schrodinger In these early days-eleven or twelve years ago -attention was focussed on electron waves in atoms. The wave mechanics had sprung from the atom,DISCOVERY OF ELECTRON WAVES 389 It looked at this time - in the year 1913 - as if the authentic key to the spectra had at last been found, as if only time and patience would be needed to resolve their riddles completely. But this hope was never fulfilled. The first brilliant triumphs of the theory were followed by yet others, but soon the going became distressingly difficult, and finally, despite the untiring ef￾forts of countless helpers, the attack came virtually to a standstill. The feeling grew that deeply as Bohr had dived he had not, so to speak, touched bottom. What was wanted, it was felt, was a new approach, a new theory of the atom which would embrace necessarily all the virtues of the Bohr theory and go beyond it - a theory which would contain some vaguely sensed unifying principle which, it was felt, the Bohr theory lacked. Such an underlying principle had been sought for almost from the first. By 1924 one or two ideas of promise had been put forward and were being assiduously developed. Then appeared the brilliant idea which was destined to grow into that marvelous synthesis, the present-day quantum mechanics. Louis de Broglie put forward in his doctor’s thesis the idea that even as light, so matter has a duality of aspects; that matter like light possesses both the properties of waves and the properties of particles. The various "restric￾tions" of the Bohr theory were viewed as conditions for the formation of standing electron wave patterns within the atom. Reasoning by analogy from the situation in optics and aided by the clue that Planck’s constant is a necessary ingredient of the Bohr’s theory, de Broglie assumed that this constant would connect also the particle and wave aspects of electrons, if the latter really existed. De Broglie assumed that, as with light, the correlation of the particle and wave properties of matter would be expressed by the relations: (Energy of particle) E = hv(frequency, i.e. waves/unit time) (Momentum of particle) p = h ( (T wave number, i.e. waves/unit distance) The latter may be written in the more familiar form l = h/p, where l rep￾resents wavelength. Perhaps no idea in physics has received so rapid or so intensive devel￾opment as this one. De Broglie himself was in the van of this development but the chief contributions were made by the older and more experienced Schrödinger. In these early days - eleven or twelve years ago - attention was focussed on electron waves in atoms. The wave mechanics had sprung from the atom