约翰内斯·里德伯Johannes Rydberg

约翰内斯·里德伯 被称为 Janne 里德伯。他的父亲 Sven R 里德伯 是一位商人，还拥有几条船，而他的母亲是 Maria Beata Andersson。然而，Sven 里德伯 在儿子 Janne 只有四岁时就去世了，家庭陷入了极其困难的财务状况。Janne 在哈尔姆斯塔德上学，该地位于瑞典西南部，卡特加特海峡东岸，尼桑河河口。在文理中学，他学习了全面的科目，包括地理、历史、语言、数学、博物学、哲学、物理和宗教。他于 1873 年在哈尔姆斯塔德的中学完成了中学教育，并于同年秋天进入隆德大学。隆德大学位于瑞典南部马尔默东北的隆德镇，是瑞典第二古老的大学，建于 1666 年。现在里德伯在所有学校科目中都表现得非常好，但他最喜欢的科目是数学，因此这是他本科学习的主要课题。

里德伯于1875年在隆德大学获得学士学位。他继续学习数学，并撰写了一篇关于conic sections的主要学位论文以获得数学博士学位，第二篇论文是关于代数函数的代数积分。他于1879年被授予博士学位。在学习数学期间，里德伯还在隆德物理研究所教授物理，他于1876年被任命为该研究所的助理。获得博士学位后，他于1880年被任命为隆德大学数学助理讲师，即讲师（Docent），但他的研究兴趣此时正转向数学物理而非纯数学。在担任数学讲师的两年里，他研究与电有关的问题。他此时进行的物理研究是实验性的而非理论性的。

1882年，里德伯从数学助理讲师转为隆德大学的物理助理讲师。同年，隆德大学关于建造新物理大楼以容纳物理研究所的请求获得批准。这个新研究所最终成为里德伯余下职业生涯的工作场所。1886年，他与Lydia Eleonora Mathilda Carlsson结婚，她是省县议会一名医务官员的女儿；他们有两个女儿和一个儿子Helge，后来成为生物学家。1897年，他接任物理学教授的职责，但这只是临时性的，他仍是一名助理讲师。由于薪水极低，里德伯被迫在当地储蓄银行担任会计，以便补充收入，足以养家糊口。1897年，里德伯申请隆德大学物理学讲席，该职位因Karl Albert Viktor Holmgren（1824-1905）退休而空缺。有六人申请该讲席，但过程持续了数年，任命程序几乎变得荒唐可笑。

我们在另一篇文章中审视此事的细节，特别是裁判对里德伯的评估。见THIS LINK

结果是，阿尔伯特·维克多·巴克隆德被任命，而裁判们认为他不值得为该职位排名。任命后，阿尔伯特·维克多·巴克隆德试图将里德伯提升为教授。不清楚阿尔伯特·维克多·巴克隆德是想纠正讲席任命的不公，还是想要一个额外的讲席任命以减轻教学负担。1901年3月，里德伯被任命为特聘教授，但直到1909年1月才成为正式教授任命。从那时起直到退休，他担任隆德大学物理学讲席。

里德伯最重要的工作是在光谱学方面，他发现了元素光谱中各谱线之间相对简单的表达式。我们引用讣告[9]（另见[11]）：-

尽管当时可用的光谱表不完善，里德伯发现了系列光谱的大部分重要性质，包括相关元素光谱中对应系列之间的关系，并预示了后来在实验工作充分进展后所做出的发现。里德伯注意到的某些特征大约同时被Kayser和卡尔·龙格观察到，但他的工作具有特殊优点，即将同一元素光谱中的不同系列联系成一个系统，该系统可由一组仅有少数可调常数的简单公式表示。他特别坚持氢常数，现在通常称为“里德伯常数”，应出现在所有系列中，并且除了尼尔斯·玻尔的理论工作所建议的元素间微小变化外，几乎所有后来改进系列表示的努力都涉及这一假设，并以里德伯的公式为基础。

我们知道他在1887年9月之前已经找到了他的结果，因为此时他写信给瑞典皇家科学院请求财政支持，并在申请中附了一份附录，列出了他后来公开宣布的结果。他首次公开宣布其结果是在On the Structure of the Line Spectra of Chemical Elements. Preliminary Notice Communicated by the Author中，该文于1890年发表。在这份初步通知中，他表示他的研究仅涉及周期表第I、II和III族的元素。然而，他确信他发现的定律适用于所有元素。他于1889年11月13日向瑞典皇家科学院提交了他的主要论文Recherches sur la constitution des spectres d'émission des élements chimiques Ⓣ（《化学元素发射光谱构成的研究》）。该论文也由科学院于1890年发表。我们现在看看里德伯在这些论文中的一些评论。

他之所以研究元素的光谱线，是因为Dmitri Ivanovich Mendeleyev（1834-1907）的工作，后者于1871年提出了元素周期表。Mendeleyev的工作起初并未受到多少热情欢迎，但多年来这种情况发生了变化。里德伯在Recherches中写道：-

随着Mendeleyev发现元素周期表，出现了一个新的出发点，对我在这里研究的所有工作都具有重大意义。然而，它被使用得很少。在《Om de kemiska》中，我得出结论，大量物理系数的周期性必定取决于这样一个事实：作用于同一元素或不同元素的两个原子之间的力是原子量的周期函数。

他指出，除了氢原子光谱的约翰·雅各布·巴耳末公式之外，:-

... 发光光谱的构成问题仍未解决，而且为比较和计算元素光谱所做的大多数尝试，其方式使得这类工作全都声名扫地，并夸大了困难，因为其作者在形成假说时让想象力过于自由地驰骋。

他给出了一个基于各种常数的公式，并指出:-

... 对应谱线的波长和波数，以及不同元素对应线系三个常数的值，都是原子量的周期函数。因此，如果周期表中两种元素的光谱已知，则可以用插值法计算它们之间元素的光谱。

他继续研究谱线问题，并在其论文Lines in the Hydrogen Spectrum（1897）中写道:-

正如我在关于线光谱构成的一般论述中已经指出的，并且后来试图进一步证实的，毫无疑问，这些线系实际上是一个具有两个可变整数参数的单一谱线群的组成部分，其一般公式可以近似地写成。

他希望确定原子的结构，尽管他的工作确实为结构理论提供了基础，但他本人并未达到这一目标。只有在Ernest Rutherford提出了他的原子模型，并且尼尔斯·玻尔和马克斯·普朗克将量子理论方法加入原子结构理论之后，才具备了为光谱数据给出正确理论解释的基础。

我们在上文已经看到，里德伯直到1909年才成为正教授。他当时54岁，但遗憾的是，他的健康很快开始恶化。他在1911年中风，虽然恢复得足以重返工作，但他开始出现心脏和循环系统问题。他的健康持续恶化，并于1914年病重。尽管他继续保有讲席，但他在1914年请了病假，从那时起就未再出现在大学。Manne Siegbahn（1886-1978）曾在1906年至1911年间是里德伯的学生，随后在1911年至1914年间担任里德伯的助手，于1914年接替了他的教学职责。他履行这些职责直到里德伯于1919年达到65岁。我们注意到，Siegbahn撰写了里德伯的传记[13]。里德伯于1915年辞去职位，并于1916年被送入医院。他在医院度过了三年，之后死于脑出血。Siegbahn在里德伯退休后于1915年成为教授，但直到1920年初，他才被任命为里德伯的物理学讲席。

[8]的作者们这样描述里德伯的性格：-

里德伯被许多同时代人视为一个复杂的人，他的悲伤显而易见，但他的谦逊和心地善良也受到赞赏。

[13]的作者写道：-

……他那种安静的幽默感，尤其是在面对那些显然无法欣赏他的人时。多年来担任隆德'Fysiska föreningen'主席的里德伯，总是乐于与学会和机构中的年轻人以及即将毕业的研究生讨论。

我们已经看到，尽管他的工作具有开创性，里德伯仍难以获得教授职位。他也未能获得诺贝尔物理学奖，尽管曾被提名1917年奖项（该年未颁奖），并再次被提名1920年奖项（他于1919年12月去世，因此不符合资格）。更令人惊讶的是，他未能当选瑞典皇家科学院。然而，在他去世前不久，1919年6月29日，他当选为伦敦皇家学会会士。可以肯定的是，他去世后获得的声誉比生前更大。1954年7月，隆德大学举行了一次会议，以庆祝他诞辰100周年。当时顶尖物理学家出席了会议，会议论文集已出版（见[3]）。出席的两位科学家是尼尔斯·玻尔，他贡献了文章[5]，以及沃尔夫冈·泡利，他贡献了文章[10]。月球上的里德伯陨石坑和小行星10506 里德伯以他的名字命名。

Johannes Robert Rydberg was known as Janne Rydberg. His father, Sven R Rydberg, was a merchant who also owned several boats, while his mother was Maria Beata Andersson. However, Sven Rydberg died when his son Janne was only four years old and the family was left in an extremely difficult financial position. Janne attended school in Halmstad which is in southwestern Sweden, on the eastern shore of the Kattegat, at the mouth of Nissan River. At the Gymnasium, he studied a full range of subjects, geography, history, languages, mathematics, natural history, philosophy, physics, and religion. He completed his secondary school education at the Gymnasium in Halmstad in 1873 and, in the autumn of the same year, he entered the University of Lund. The University of Lund, in the town of Lund in southern Sweden northeast of Malmo, is the second oldest university in Sweden being founded in 1666. Now Rydberg had performed very well in all his school subjects but his favourite one had been mathematics so this was the major topic of his undergraduate studies.

Rydberg received his bachelor's degree in 1875 from the University of Lund. He continued his study of mathematics and wrote a main dissertation on conic sections for his doctorate in mathematics with a second thesis on algebraic integrals of algebraic functions. He was awarded his doctorate in 1879. While he was studying mathematics, Rydberg also taught physics at the Lund Physics Institute where he had been appointed as an assistant in 1876. After the award of his doctorate, in 1880 he was appointed to the post of assistant lecturer, or docent, in mathematics at Lund University but his research interests were now turning towards mathematical physics rather than to pure mathematics. During his two years as a lecturer in mathematics he worked on problems relating to electricity. The physics research he undertook at this time was experimental rather than theoretical.

In 1882 Rydberg moved from an assistant lectureship in mathematics to become an assistant lecturer in physics at the University of Lund. In the same year the University of Lund's request for a new physics building to house the Institute of Physics was approved. This new Institute would eventually become Rydberg's place of work for the rest of his career. In 1886 he married Lydia Eleonora Mathilda Carlsson, the daughter of a medical official to the provincial county council; they had two daughters and a son Helge who became a biologist. In 1897 he took over the duties of the professor of physics but this was only on a temporary basis and he remained an assistant lecturer. With an extremely poor salary, Rydberg was forced to take a position as an accountant in a local saving bank so that he could supplement his income sufficiently to allow him to support his family. In 1897 Rydberg applied for the chair of physics at the University of Lund which became vacant when Karl Albert Viktor Holmgren (1824-1905) retired. Six people applied for the chair but the process went on several years and the appointing procedure became almost farcical.

We look at the details of this, and in particular at the referee's assessment of Rydberg, in a separate article. See THIS LINK

The outcome was that Albert Victor Bäcklund, who was an applicant that the referees had considered as not worth ranking for the position, was appointed. After his appointment, Bäcklund tried to get Rydberg promoted to professor. It is unclear whether Bäcklund was trying to right the wrong of the chair appointment or whether he wanted an additional chair appointment so that he had a lighter teaching load. In March 1901 Rydberg was named as an extraordinary professor but it only became a full professorial appointment in January 1909. From this time until his retirement he held the chair of physics at Lund.

Rydberg's most important work is on spectroscopy where he found a relatively simple expression relating the various lines in the spectra of the elements. We quote from the obituary [9] (see also [11]):-

Notwithstanding the imperfect spectroscopic tables then at his disposal Rydberg discovered most of the important properties of series spectra, including the relation between corresponding series in the spectra of related elements, and foreshadowed discoveries which were made later, when experimental work has sufficiently advanced. Some of the features noted by Rydberg were observed about the same time by Kayser and Runge, but his work had the special merit of connecting different series in the spectrum of the same element into one system, which could be represented by a set of simple formulae having but few adjustable constants. He especially insisted that the hydrogen constant, now generally called the "Rydberg constant," should appear in all series and, apart from slight variations from element to element suggested by the theoretical work of Bohr, nearly all subsequent attempts to improve the representation series have involved this supposition, and have had Rydberg's formula as a basis.

We know that he had found his results by September 1887 since he wrote to the Royal Swedish Academy of Sciences at this time requesting financial support and attached to his application an appendix listing the results he later announced publicly. His first public announcement of his results was in On the Structure of the Line Spectra of Chemical Elements. Preliminary Notice Communicated by the Author which was published in 1890. In this preliminary notice, he stated that his researches had been only on elements in groups I, II, and III of the periodic table. However, he was certain that the laws he had found applied to all elements. He had presented his main paper Recherches sur la constitution des spectres d'émission des élements chimiques Ⓣ to the Royal Swedish Academy of Sciences on 13 November 1889. It also was published by the Academy in 1890. We now look at some of Rydberg's comments in these papers.

He had been led to study spectral lines of elements because of the work of Dmitri Ivanovich Mendeleyev (1834-1907) who had produced his periodic table of the elements in 1871. Mendeleyev's work was, at first, greeted with little enthusiasm but this changed over the years. Rydberg writes in Recherches:-

With the discovery by Mendeleyev of the periodic table of elements, there has arisen a new point of departure of great importance for all the work which I study here. However, it has been used but little. In 'Om de kemiska' I have concluded that the periodicity of a great number of physical coefficients must depend on the fact that the force which acts between two atoms of the same, or of different elements, is a periodic function of the atomic weight.

He states that, except for the Balmer formula for the spectrum of the hydrogen atom, the:-

... problem of the constitution of luminous spectra is still unsolved and most of the attempts that have been made to compare and calculate the spectra of the elements have been done in such a way as to throw discredit on all work of this kind and to exaggerate the difficulties their authors having let their imaginations run so freely in the formation of their hypothesis.

He gives a formula based on various constants and notes that:-

... the wave-lengths and wave numbers of corresponding lines, as well as the values of the three constants of the corresponding series of different elements, are periodical functions of the atomic weight. Therefore, if the spectra of two elements in the periodic table are known, the spectrum of the element in between them can be calculated using interpolation.

He continued to study the problem of spectral lines and in his paper Lines in the Hydrogen Spectrum (1897) he writes:-

As I have pointed out already in my general exposition of the constitution of line spectra, and have afterwards tried further to confirm, there can be no doubt that these series are really parts of a single group of lines with two variable integral parameters, the general formula of which can be written approximately.

He hoped to determine the structure of the atom but, although his work did provide the basis for the structure theory, he himself did not reach his goal. Only after Ernest Rutherford had proposed his model of the atom, and Niels Bohr and Max Planck had added a quantum theory approach to the theory of atomic structure, was the foundation in place to give a correct theoretical account of spectral data.

We have seen above that Rydberg only became a full professor in 1909. He was 54 years old, but sadly his health soon began to deteriorate. He had a stroke in 1911 and, although he recovered sufficiently to return to work, he began to suffer heart and circulation problems. His health continued to deteriorate and he became seriously ill in 1914. Although he continued to hold the chair he took sick leave in 1914 and was absent from the university from that time on. Manne Siegbahn (1886-1978), who had been a student of Rydberg from 1906 to 1911, then Rydberg's assistant from 1911 to 1914, took over his teaching duties in 1914. He carried these out until Rydberg reached the age of 65 in 1919. We note that Siegbahn wrote the biography of Rydberg [13]. Rydberg resigned his position in 1915 and in 1916 he was taken into hospital. He spent three years in hospital before dying from a brain haemorrhage. Siegbahn became a professor in 1915 when Rydberg retired but it was only early in 1920 that he was appointed to Rydberg's chair of physics.

The authors of [8] write about Rydberg's character:-

Rydberg was considered by many of his contemporaries as a complicated person and his sadness was apparent, but his modesty and kindliness of heart were also appreciated.

The author of [13] writes about:-

... his quiet sense of humour especially when concerned with those who were apparently unable to appreciate him. For years chairman of the 'Fysiska föreningen' in Lund, Rydberg was always interested in discussions with the younger men in the society and the institution, and with graduate students nearing their goal.

We have already seen that, despite his groundbreaking work, Rydberg struggled to get a professorial appointment. He also failed to receive the Nobel prize for physics despite being nominated for the 1917 prize (no award was made that year) and again for the 1920 prize (his death in December 1919 meant he was not eligible). Even more surprising is that he failed to get elected to the Royal Swedish Academy of Sciences. However, shortly before his death, on 29 June 1919, he was elected a fellow of the Royal Society of London. Certainly he has achieved more fame after his death than during his lifetime. A conference was held at the University of Lund in July 1954 to celebrate the 100th anniversary of his birth. It was attended by the leading physicists of the day and the proceedings was published (see [3]). Two of the scientists who attended were Niels Bohr, who contributed the article [5], and Wolfgang Pauli, who contributed the article [10]. The crater Rydberg on the Moon and asteroid 10506 Rydberg have been named in his honour.