Theory of the Zeeman effect in the band lines of rigid diatomic molecules.—The qualitative features of the Zeeman effect in the band lines of rigid diatomic molecules as given by the conventional quantum theory and the new quantum mechanics are the same. Both predict that the Zeeman pattern for electronic transitions of the type ${}_{}{}^1{}_{}{}^{}S\to {}_{}{}^1{}_{}{}^{}P$ will be greatest for the first line in each branch (for which $M$, the empirical serial number of a line in a branch, is 1) and will increase in complexity ($N=\mathrm{number}\mathrm{of}\mathrm{component}\mathrm{lines}\mathrm{in}\mathrm{a}\mathrm{pattern}=2M+1\mathrm{}$) and decrease in scale as $M$ increases. The size of the pattern is $\frac{2}{(M+1+\frac{1}{4M})}·\Delta {\nu }_n$ on the old and $\frac{2}{\mathrm{}(M+1\mathrm{})\mathrm{}}·\Delta {\nu }_n$ on the new quantum theory. For $M>\mathrm{}2\mathrm{}$ the size of the pattern is almost exactly the same for both theories.

Measurement of the Zeeman effect in the $\lambda \lambda 5610$, 5198 and 4835 bands of CO.—Results on the $\lambda \lambda 5610$, 5198 and 4835 bands of CO are in agreement with the theoretical predictions. The effect is proportional to the field strength and the patterns are symmetrical about the positions of the lines with no field. Eight of the possible twelve patterns observable for the first two lines of the $P$ and $Q$ branches have been resolved, the rest together with all of the patterns for $R\left(1\right)\mathrm{}$ and $R\left(2\right)\mathrm{}$ being too faint for observation. With both polarizations superposed $P\left(1\right)\mathrm{}$ and $Q\left(1\right)\mathrm{}$ give symmetrical triplets of total width of 95 percent of $\Delta {\nu }_n$, thus falling almost exactly midway between the predictions of the two theories. The lines with $M>\mathrm{}2\mathrm{}$ are only partially resolved but give patterns which are characteristic and are in agreement with intensity predictions based both on the summation rule and the correspondence principle and on the quantum mechanics. The higher $Q$ lines appear as doublets in the parallel polarization, and broad singlets in the perpendicular polarization. The $P$ and $R$ branches in the two polarization show a similar, but reversed and less pronounced difference in character. A fact not accounted for by theory is the slightly greater intensity of the low-frequency components of the $Q$ doublets (parallel polarization) and of the high-frequency components of the $P$ doublets (perpendicular polarization). The results completely confirm the assignment by R. S. Mulliken of the CO Angstrom bands to electronic transitions of the type ${}_{}{}^1{}_{}{}^{}S\to {}_{}{}^1{}_{}{}^{}P$ with ${\sigma }^{\prime }=0\mathrm{}$ and ${\sigma }^{\prime \prime }=1\mathrm{}$, where $\sigma$ is the electronic angular momentum parallel to the nuclear axis and single and double primes refer respectively to the initial and final states.

Close

PrevNext

View figure in article