HEISENBERG, WERNER.

Über die Spektra von Atomsystemen mit zwei Elektronen.

Berlin, Springer, 1926. 8vo. Bound in contemporary half cloth. In "Zeitschrift für Physik", Bd. 39. Entire volume offered. Stamp to front free end paper. Fine and clean. Pp. 499-518. [Entire volume: IV, 948 pp].

First edition of this important paper in which Heisenberg - after inventing Quantum Mechanics the year before (1925) - investigates some of the fundamental aspects of the new theory.

Heisenberg recognizes the invariance of the wave equation with respect to various transformations. "It is clear that such invariance exists with respect to an interchange of the coordinates of identical particles, e.g. of two electrons in an atom of two nuclei of the same kind in a molecule. As a consequence, the wave function of a non-degenerate stationary state must either remain unchanged or may only change sign when the transformation is applied to it....Indeed, in this way Pauli's exclusion principle for electrons found a formulation in terms of wave mechanics."(K. Kronik in Memorial Volume to Wolfgang Pauli).

Cassidy 1926e

Order-nr.: 49432