古斯塔夫·赫兹Gustav Ludwig Hertz

古斯塔夫·赫兹的父母是赫兹和Auguste Arning。赫兹（老）是一名律师，他是海因里希·鲁道夫·赫兹的兄弟之一，后者是无线波的发现者，在本档案中也有传记。本传记的主人公赫兹，像他著名的叔叔大约三十年前那样，在汉堡的Johanneum 文理中学（Gymnasium）就读。他于1906年从Johanneum毕业，进入哥廷根大学学习物理学。

按照当时德国学生的惯例，赫兹并未在单一大学完成学业，而是辗转于多所院校以汲取各家之长。离开哥廷根后，赫兹前往慕尼黑，在该大学学习，随后于1909年转至柏林大学攻读博士学位。1911年，他凭借学位论文Über das ultrarote Absorptionsspektrum der Kohlensäure in seiner Abhängigkeit von Druck und PartialdruckⓉ（《二氧化碳红外吸收光谱对压强和分压的依赖关系》）获得博士学位，该论文由Heinrich Rubens和马克斯·普朗克指导。在论文中，他研究了二氧化碳的红外吸收与压强和分压的关系。

1913年，赫兹被任命为柏林大学物理学助理。在柏林，他与James Franck共事。Franck比赫兹年长五岁，于1909年获得柏林大学博士学位。两人于1913年开始合作研究项目，一直持续到1914年7月至8月第一次世界大战爆发。战争爆发后，赫兹和Franck均被征召入伍，他们的研究合作被迫中断。然而，他们所完成的工作使两人于1925年共同获得诺贝尔物理学奖。他们的工作通过表明当电子撞击汞蒸气原子时，电子必须拥有某一最低能量才能被原子吸收，从而在实验上证实了尼尔斯·玻尔提出的量子理论。此外，即使电子拥有的能量超过这一最低值，也只有恰好等于最低值的能量被吸收。

战争对赫兹来说是不幸的，他在1915年的战斗中受了重伤。康复后，他于1917年被任命为柏林大学的Privatdozent。担任此职位期间，他于1919年与Ellen Dihlmann结婚。他们有两个儿子，Carl Hellmuth Hertz，生于1920年10月15日，以及Johannes Hertz，两人都成为了物理学家。赫兹于1920年离开柏林，在埃因霍温的飞利浦白炽灯厂的物理实验室工作了五年。1925年，他被任命为哈勒大学的物理学教授和物理研究所所长。在1925年获得诺贝尔物理学奖后，赫兹于1926年12月11日作了题为“根据尼尔斯·玻尔原子理论看电子碰撞实验的结果”的诺贝尔演讲。在那次演讲中，他介绍了其极其重要的实验结果的背景：-

电子碰撞导致原子电离的研究之所以重要，是因为它们为尼尔斯·玻尔原子理论的基本假设提供了直接的实验证明。……原子能够与电磁辐射交换能量这一事实，使经典物理学家得出结论：原子必须包含运动的电荷。这些电荷的振荡产生光辐射的发射，而光的吸收则被归因于这些电荷由于光波的电场而被迫振荡。根据亨德里克·洛伦兹关于正常埃里克·克里斯托弗·齐曼效应、谱线磁致分裂的理论，可以得出结论：这些运动的电荷必定是我们在阴极射线中所熟悉的电子。如果每种原子只与一条或几条谱线相关联，那么或许可以假设原子为每条谱线包含一个具有相应特征频率的电子。然而实际上，每个原子发射的谱线数量是无限多的。谱线当然不是随机分布的，相反，它们的频率之间存在某种关系，但这种关系使得在经典物理学的基础上不可能用电子系统的特征频率来解释它。在这里，尼尔斯·玻尔带着他的原子理论介入了。他将马克斯·普朗克的量子理论应用于原子结构和光发射问题，从而极大地扩展了这一理论。

1928年，他被任命为柏林夏洛滕堡技术大学物理研究所所长。他此时的主要任务较少涉及研究，更多是行政方面的工作，他致力于重建物理研究所。然而，他确实继续进行研究，并在1932年取得了另一项重大突破，他设计了一种分离氖同位素的方法。他的祖父是犹太人，因此当纳粹党于1933年上台时，他的处境变得困难。1933年4月7日，纳粹通过了一项法律，根据第三条款，命令非雅利安血统的公务员退休，但对第一次世界大战参与者和战前官员有豁免。赫兹符合豁免条件，但在随后的时期这一豁免并未得到兑现。赫兹于1935年辞去柏林技术大学的职务，重返工业界，被任命为西门子物理实验室主任。1941年，赫兹的妻子Ellen去世。两年后，他与Charlotte Jollasse再婚。

1945年战争结束后，赫兹前往苏联，在那里担任一个研究实验室的负责人。1954年返回东德后，他被任命为莱比锡卡尔·马克思大学的教授和物理研究所所长。他一直担任此职位，直到1961年退休。退休后，他继续在莱比锡住了一段时间，然后搬到柏林，在那里度过了他生命的最后几年。

除了1925年的诺贝尔物理学奖外，赫兹还获得了许多荣誉。与诺贝尔奖一样，他于1951年与James Franck共同获得了德国物理学会的马克斯·普朗克奖章。此外，他还当选为哥廷根科学院、Hungarian Academy of Sciences、Czech Academy of Sciences和苏联科学院的成员。

Gustav Hertz's parents were Gustav Hertz and Auguste Arning. Gustav Hertz (senior) was a lawyer who was one of the brothers of Heinrich Hertz, the discoverer of wireless waves, who also has a biography in this archive. Gustav, the subject of this biography, attended the Johanneum Gymnasium in Hamburg as his famous uncle had done about thirty years earlier. He graduated from the Johanneum in 1906 and entered the University of Göttingen to study physics.

As was the custom with German students at this time, Hertz did not complete his studies at a single university, but moved around to sample the best of a number of institutions. After Göttingen, Hertz moved to Munich where he studied at the university before moving to the University of Berlin in 1909 to study for his doctorate. In 1911 he was awarded his doctorate for his thesis Über das ultrarote Absorptionsspektrum der Kohlensäure in seiner Abhängigkeit von Druck und Partialdruck Ⓣ which he had written with Heinrich Rubens and Max Planck as advisors. In his thesis he studied the infrared absorption of carbon dioxide in relation to pressure and partial pressure.

In 1913 Hertz was appointed as an Assistant in Physics at the University of Berlin. At Berlin he worked with James Franck. Franck was five years older than Hertz and had been awarded his doctorate by the University of Berlin in 1909. The two began their joint research project in 1913 and continued it until the outbreak of World War I in July-August 1914. Both Hertz and Franck were mobilised when war broke out and their research collaboration necessarily stopped. However the work they had done led to their being jointly awarded the Nobel Prize for Physics in 1925. Their work confirmed experimentally quantum theory as proposed by Bohr by showing that when an electron strikes an atom of mercury vapour, it must possess a certain minimum energy before that energy is absorbed by the atom. Moreover even if the electron had more than this minimum energy, it was only the exact minimum energy which was absorbed.

The war proved unfortunate for Hertz who was severely wounded in action in 1915. After he recovered he was appointed as a Privatdozent at the University of Berlin in 1917. While holding this post he married Ellen Dihlmann in 1919. They had two sons, Carl Hellmuth Hertz, born on 15 October 1920, and Johannes Hertz who both became physicists. Hertz left Berlin in 1920 and worked for five years in the physics laboratory of the Philips Incandescent Lamp Factory at Eindhoven. In 1925 he was appointed Professor of Physics and Director of the Physics Institute at the University of Halle. After being awarded the Nobel Prize for Physics in 1925, Hertz gave his Nobel lecture on The results of the electron-impact tests in the light of Bohr's theory of atoms on 11 December 1926. In that lecture he gave the background to his highly significant experimental results:-

The significance of investigations on the ionization of atoms by electron impact is due to the fact that they have provided a direct experimental proof of the basic assumptions of Bohr's theory of atoms. ... The fact that atoms are capable of exchanging energy with electromagnetic radiation, led the classical physicists to conclude that atoms must contain moving electrical charges. The oscillations of these charges produce the emission of light radiation, while light absorption was ascribed to forced oscillations of these charges owing to the electrical field of the light waves. On the basis of Lorentz's theory of the normal Zeeman effect, of the magnetic splitting of the spectral lines, it was concluded that these moving charges must be the electrons to which we are acquainted in cathode rays. If only one or several spectral lines were associated with each type of atom, then it might be assumed that the atom contained, for each spectral line, an electron of corresponding characteristic frequency. In reality, however, the number of spectral lines emitted by each atom is infinitely large. The spectral lines are certainly not randomly distributed, on the contrary there exists a certain relationship between their frequencies, but this relationship is such that it is impossible on the basic of classical physics to explain it in terms of the characteristic frequencies of a system of electrons. Here Bohr stepped in with his atomic theory. He applied Planck's quantum theory to the problem of atomic structure and light emission, and thereby greatly extended this theory.

In 1928 he was appointed Director of Physics Institute, Charlottenburg Technological University, Berlin. His main task now was less involved with research and more on the administrative side as he worked to rebuild the the Physics Institute. He did, however, continued at undertake research and, in 1932, he made another significant breakthrough when he devised a method of separating the isotopes of neon. He had a grandfather was was Jewish and so when the Nazi Party came to power in 1933 his position became difficult. On 7 April 1933 the Nazis passed a law which, under clause three, ordered the retirement of civil servants who were not of Aryan descent, with exemptions for participants in World War I and pre-war officials. Hertz qualified under the exemptions, but this was not honoured over the following period. Hertz resigned his positions at the Technological University of Berlin in 1935 and returned to industry being appointed Director of the Siemens physics laboratory. In 1941 Hertz's wife Ellen died. He married again two years later to Charlotte Jollasse.

When the war ended in 1945 Hertz went to the Soviet Union where he worked as the head of a research laboratory. Returning to East Germany in 1954, he was appointed Professor and Director of the Physics Institute at the Karl Marx University in Leipzig. He held this position until he retired in 1961. After he retired he continued to live for a while in Leipzig, but then moved to Berlin where he spent the last years of his life.

Hertz received many honours in addition to the 1925 Nobel Prize in Physics. As with the Nobel Prize, he received the Max Planck Medal of the German Physical Society in 1951 jointly with James Franck. In addition he was elected to the Göttingen Academy of Sciences, the Hungarian Academy of Sciences, the Czech Academy of Sciences, and the USSR Academy of Sciences.