Transient-field $g$-factor measurements in inverse kinematics were performed for the first-excited states of the stable, even isotopes of Ge and Se. The $g$ factors of $^{74}$Ge and $^{74}$Se were measured simultaneously using a cocktail beam, which eliminates most possible sources of systematic error in a relative $g$-factor measurement. The results are $g(^{74}{rm Se})/g(^{74}{rm Ge})=1.34(7)$, $g(^{70}{rm Ge})/g(^{74}{rm Ge}) = 1.16(15)$, $g(^{72}{rm Ge})/g(^{74}{rm Ge})=0.92(13)$, $g(^{76}{rm Ge})/g(^{74}{rm Ge})=0.88(5)$, $g(^{76}{rm Se})/g(^{74}{rm Se})=0.96(7)$, $g(^{78}{rm Se})/g(^{74}{rm Se})=0.82(5)$, $g(^{80}{rm Se})/g(^{74}{rm Se})=0.99(7)$ and $g(^{82}{rm Se})/g(^{74}{rm Se})=1.19(6)$. The measured $g$-factor ratios are in agreement with ratios from previous measurements, despite considerable variation in previous reported absolute values. The absolute values of the $g$ factors remain uncertain, however the Rutgers parametrization was used to set the transient-field strength and then compare the experimental $g$ factors with shell-model calculations based on the JUN45 and jj44b interactions. Modest agreement was found between experiment and theory for both interactions. The shell model calculations indicate that the $g(2^+_1)$ values and trends are determined largely by the balance of the spin carried by orbital motion of the protons.
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