Molecular structure and chemical bonding in ${\mathrm{K}}_3$${\mathrm{C}}_{60}$ and ${\mathrm{K}}_6$${\mathrm{C}}_{60}$

We present the results of local-density-approximation-based Car-Parrinello calculations of orientationally ordered phases of ${\mathrm{K}}_3$ ${\mathrm{C}}_{60}$ and ${\mathrm{K}}_6$ ${\mathrm{C}}_{60}$. Our investigation focuses on the following points: the effects of alkali-mental intercalation on the structural and electronic properties of ${\mathrm{C}}_{60}$, the chemical bonding, the inhomogeneity of the electron distribution, and the degree of freedom of the potassium atoms in the interstitial region. The results are discussed in view of experimental data, such as x-ray and neutron-diffraction data as well as nuclear magnetic resonance spectroscopy.