Insight into the vertical detachment energy oscillation of NanC60− clusters

Abstract

We have performed a detailed density functional theory study on the structural and electronic properties of Na(n)C(60)(-) (n = 1-12) clusters. The calculated vertical detachment energies show good agreement with the experimental data, which confirms the 3p (n = 3p) oscillation rule. The oscillation can be attributed to the combination of the charge depletion distribution induced by removing electrons and the number of the sodium atoms in direct contact with the fullerene. Based on the structural and electronic properties, the Na atoms can be categorized into two groups, one is for the metal atoms directly bonded to the fullerene surface, and the other one is for those without bonding to the fullerene. The Na atoms in group one would donate electrons to both the fullerene and the Na atoms in group two. As the total number of the sodium atoms increases, the number of Na atoms in group one would continue increasing till the size n = 3p - 1 to meet a shoulder from n = 3p - 1 to n = 3p, which accounts for the maximum vertical detachment energy at the size of n = 3p as drawn from the detailed electronic property studies.

Adsorption of sodium and cesium on aggregates of C60

“…Spectra of C 60 Na − n (n 12), however, suggest that sodium atoms on C 60 tend to form trimers or perhaps tetrahedral tetramers rather than uniformly covering C 60 as expected if Coulomb repulsion between the adsorbed cations would prevail [47][48][49], in agreement with the theoretical work mentioned above [37].…”

Positively and Negatively Charged Cesium and (C60)mCsn Cluster Ions

“…One should emphasize though that previous work mostly pertains to the lighter alkalis (A = Li, Na, K) and that their properties are still debated. 30 …”

“…For n = 4, 6, 7, 9 the ground state structure consists of a single three-dimensional sodium cluster, while for n = 5 and 8 two isolated clusters form on opposite sides of the fullerene. 30 …”

Absorption spectra of alkali-C60nanoclusters

“…Many experimental and theoretical studies have been devoted to the electronic and structural properties of C60Mn clusters, with M=Li, Na, K [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]. Very early, the strong stability of C60Li12 was interpreted as a signature of a homogeneous coating of the fullerene by all lithium atoms above the twelves pentagonal faces of the C60 molecule resulting in an icosahedral arrangement [12][13][14].…”

“…However, when several alkali atoms lie on a fullerene, the hydrogen adsorption capacity greatly depends on the wetting or nonwetting of the fullerene surface with alkali atoms: an homogenous coating of the fullerene by the alkali atoms is expected to be much more efficient than the growth of a metallic droplet not wetting the fullerene surface which could drastically limit the amount of stored hydrogen. Many experimental and theoretical studies have been devoted to the electronic and structural properties of C 60 M n clusters, with M = Li, Na, K. [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] Very early, the strong stability of C 60 Li 12 was interpreted as a signature of a homogeneous coating of the fullerene by all lithium atoms above the twelve pentagonal faces of the C 60 molecule resulting in an icosahedral arrangement. [12][13][14] In contrast, coating the fullerene with sodium or potassium atoms led to an even-odd alternation in the mass spectra, suggesting the onset of metallic bonding.…”