Wiederkehr Karl Heinrich
Universität Hamburg, Birkenau 24, 22087 Hamburg.
Sudhoffs Arch. 2006;90(2):132-42.
It is generally supposed, that the discovery of the efficacy-quantum by Planck was the impetus to Einstein's hypothesis of lightquanta. With its help Einstein could explain the external light-electrical effect. But even years before Einstein had worked at the photoeffect and already made experiments on it. For that reason the article gives a short survey about the history of the lightelectric effects. Lenard's basical work about the release of the photoelectrons is dealt with in detail, without which Einstein would scarcely have found his lightquanta. Furthermore it is shown how difficult it was for the physicists to give up--at least partially--the traditional view of the undulation-nature of light, and how they searched to explain the great energies of the photoelectrons. On the other side it is set forth how Einstein's formula of lightquanta was gradually confirmed. The tragical development of Einstein's personal relations with Johannes Stark and Philipp Lenard are briefly described. Stark was one of the few who supported Einstein's ideas at the beginning. Only with the Compton-effect, which could only be quantitatively interpreted by means of lightquanta and the special theory of relativity 1923, the way was free for the general acceptance of the lightquanta. Einstein did not agree to the obtained dualism of undulation and corpuscle; he had a different solution in mind about the fusion of the two forms of appearance of light.
人们普遍认为，普朗克对作用量子的发现是爱因斯坦提出光量子假说的推动力。借助这一假说，爱因斯坦能够解释外部光电效应。但早在几年前，爱因斯坦就已研究光电效应并进行了相关实验。因此，本文对光电效应的历史做了简要概述。详细讨论了勒纳德关于光电子发射的基础工作，若没有这项工作，爱因斯坦几乎不可能发现他的光量子。此外，还展示了物理学家要至少部分地放弃光的波动本质这一传统观点是多么困难，以及他们如何试图解释光电子的巨大能量。另一方面，阐述了爱因斯坦的光量子公式是如何逐渐得到证实的。简要描述了爱因斯坦与约翰内斯·斯塔克和菲利普·勒纳德个人关系的悲剧性发展。斯塔克是最初支持爱因斯坦观点的少数人之一。直到1923年康普顿效应出现，该效应只能用光量子和狭义相对论进行定量解释，光量子才得以被普遍接受。爱因斯坦不同意由此产生的波动与粒子的二元性；他对光的两种表现形式的融合有不同的想法。
