D O C U M E N T 3 2 1 F E B R U A R Y 1 9 2 0 4 3 9
führt, usw., wobei die Wechselwirkung zu einem völligem Auseinanderfahren der
Bestandteile des -Moleküls ausartet.
3.) Eine Abhilfe schiene mir ev. möglich, indem man auch die Bewegung der
Atomkerne nach Bohrschem Muster
quantelt.[3]
Da aber für den Bohrschen Rota-
tor die Summe nicht konvergiert, müsste man etwa nach dem Vorgange
C. F. Herzfelds durch Einführung der Weglänge die Reihe
abschneiden.[4]
—————
Leider kann ich garnicht übersehn, ob diese Gedanken (auf einem mir z. Zt. lei-
der noch unzugänglichem Gebiet) nicht grobe Fehler enthalten. Deswegen habe ich
mir erlaubt sie Ihnen in Grundzügen mitzuteilen und Sie zu bitten mir in zwei Zei-
len wissen zu lassen, ob die obige Spur von Wert sein kann. Diesfalls würde ich
hierüber eine kurze Notiz veröffentlichen,—da die Ausarbeitung mir jedenfalls zu
schwierig ist.
Meinen verbindlichsten Dank erlaube ich mir Ihnen in Voraus auszusprechen. In
grösster Hochachtung ganz ergeben
M Polányi
ALSX. [19 099]. The date and underlining are in another ink.
[1]Michael (Mihály) Polányi (1891–1976) had obtained a medical doctorate in 1913 and a doctor-
ate in physical chemistry in 1917 at the University of Budapest. He returned to Karlsruhe and, later
in 1920, he moved from Karlsruhe to Berlin to accept a position at Fritz Haber’s Kaiser Wilhelm Insti-
tute for Physical Chemistry (see Nye 2002).
[2]Einstein gave a talk five weeks earlier at the Academy on the moment of inertia of the hydrogen
molecule (Preußische Akademie der Wissenschaften (Berlin). Sitzungsberichte I (1920): 65; see entry
of 15 January 1920 in Calendar). He there explained that by applying Tetrode’s theory of the entropy
constant (Tetrode 1915) to the degrees of freedom in the rotational movement of the hydrogen mole-
cule, one can calculate from the curve of specific heats the exact moment of inertia of the molecule
without recourse to quantum theory. Although he announced a forthcoming paper on the topic, it was
never published. Einstein had last written, together with Otto Stern, about the specific heats of gases
in late 1912 (Vol. 4, Doc. 11), where he showed how the “zero-point energy” may affect physical phe-
nomena. Less than a year later he retracted his findings (see Vol. 4, the editorial note, “Einstein and
Stern on Zero-Point Energy,” pp. 270–273). Einstein also gave a closely related talk at the meeting of
the Deutsche Physikalische Gesellschaft on 14 January 1916 (Vol. 6, Doc. 26).
[3]The classical solution to this problem was given in Born and Oppenheimer 1927, where the
approximation of separating nuclear and electron wave functions for the quantum mechanics of
diatomic molecules is justified.
[4]In Herzfeld 1916, the problem that the partition function of the hydrogen atom
diverges for is addressed by arguing that in a hydrogen gas the elec-
tron quantum states associated with large n also have a large radius and are suppressed as a conse-
quence of neighboring molecules. On the basis of this assumption, Herzfeld also calculates the
dissociation (ionization) of the hydrogen atom and compares it to the quantum theoretical formula for
the dissociation of a diatomic gas.
H2
e
–--------nε
κT
n 0 =
n=∞
∑
kT)) ( ⁄ –En exp( ∑ En 1 n2 ⁄ ∼