Knowledge Bank

ESR spectra assigned to pseudorotating $\mathrm{<mrow\; data-mjx-texclass="ORD">6</mrow>}Li3$, and $\mathrm{<mrow\; data-mjx-texclass="ORD">7</mrow>}Li3$, molecules have been produced by are lamp photolysis of argon matrices doped with isotopically enriched $\mathrm{<mrow\; data-mjx-texclass="ORD">6</mrow>}Li$ or $\mathrm{<mrow\; data-mjx-texclass="ORD">7</mrow>}Li$. The spectrum of $\mathrm{<mrow\; data-mjx-texclass="ORD">6</mrow>}Li$, consists of 7 equally spaced first derivative transitions with relative intensities (1.1:3.3:6.2:7.0:5.7:3.0.1.1) in good agreement with the expected values for 3 equivalent 1 = 1 nuclei. The measured hf constant and g value are 12.21(1) G and $go$ 2.00282(1). The absence of a ``stationary” trimer spectrum suggests that the ground vibronic state of $Li8$ is non-localized as predicted by ab initio calculations. The total isotropic spin population of the triner $(\Sigma 0=0.68)$ suggests that the unpaired electron wave function has an approximately 30% p-character. A comparison of the orbital composition of $M,M2,M3,M\infty (M=Li,Na,K)$ shows (1) a diminishing s-character with increasing cluster size, (11) a remarkable similarity between Na and K cluster far all sizes, and (iii) a markedly smaller s-character for Li clusters. $\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}$W.H. Gerber and C. Schunacher, J. Chem. Phys. 69, 1697 (1978).