Shou Chin Wang (Wang Shoujing) was one of the few Chinese physicists who made significant contributions to the early development of quantum mechanics. One of his representative
works is the study on the van der Waals potential based on quantum mechanics. Specifically,
using the second-order perturbation theory in quantum mechanics, he derived a long-range
attractive potential of the form −1/R6 between two widely separated atoms. Since individual
atoms are non-polar, meaning their average dipole moments are zero, this interaction arises
from fluctuations in the instantaneous electric dipole moments of the two atoms.
Subsequently, Fritz London conducted a more systematic study of the interaction potential
between non-polar molecules. In later literature and textbooks, this result is commonly referred
to as the London dispersion force. London’s work indeed contains more extensive physical
contents, but its core conclusion—the long-range behavior of the van der Waals potential—is
consistent with Wang’s result. Wang’s work was published in Physikalische Zeitschrift, 28,
663 (1927), while London’s work appeared in Zeitschrift fur Physik, 60, 491 (1930). Wang’s
publication was clearly earlier, and London cited Wang’s work. Hence, it would be appropriate
to refer to this effect jointly as the “Wang-London force.”
For quantum chemistry, Wang’s 1927 paper is one of the important early works in this
direction. However, Wang’s research on the van der Waals attraction is not widely known in
the academic community. For example, it was not included in the collection of classic papers,
Quantum Chemistry—Classic Scientific Papers, edited by H. Hettema.
The original German text of Wang’s article is not easy to find. I would like to thank my
former student, Shenglong Xu (now an assistant professor at Texas A&M University), who
helped me find an electronic version. I do not understand German and inquired with many
people about an English translation of this article, but none could be found. The lack of an
easily accessible English translation may be one reason why this work is not well-known.
To facilitate reading, I used Google Translate to translate Wang’s article into English. I
also thank Professor Honghao Tu of Ludwig-Maximilians-Universit¨at M¨unchen, who proofread
the translated draft and provided many valuable suggestions. During the translation and review
process, some typographical errors in the original German text were identified and marked with
translator’s and reviewer’s notes.
On the centennial of the establishment of quantum mechanics, we believe it is meaningful
to translate this classic paper by Shou Chin Wang into English.
