Theoretical study of stepwise hydrogenated closo-alane clusters Al13H m − (m = 1–12)

Large gallanes and the PSEPT theory: a theoretical study of Ga n H n+2 clusters (n = 7–9)

“…After boranes, alanes with the empirical formulae Al n H m (m 0 n and m 0 n+2) are the next most popular set of neutral group 13 hydrides to study [2][3][4][5][6][7][8][9][10]; the first such cluster was characterized by Bowen and coworkers [7] using infrared spectroscopy with a pulsed arc cluster ionization source (PACIS) [11]. Their study prompted an active field of research into species that are designed to store as much hydrogen as possible [12][13][14][15][16][17][18][19][20].…”

Theoretical study of association of acetylene, benzene, and carbonyl molecules “squeezed” inside fullerene cages

“…Several dozens of comprehensive reviews cover ing state of the art theoretical studies of this problem with the use of model physical approaches and most precise quantum chemical methods have been reported in [1, 2] (see also [3,4]). Previously [5][6][7][8][9][10][11], using the density functional theory method (B3LYP approximation with the 6 31G and 6 31G* basis sets), we calculated the potential energy surfaces (PESs), equilibrium struc tures, energies, and spectroscopic properties for sev eral series of endohedral clusters L@C n , L@C n H m , and others, in which covalent molecules or their ions L with filled electronic shells (tetrahedral МН 4 hydrides, МНаl 4 halides, and М oxyanions; linear СО 2 and CS 2 chalcogenides and acetylene; cyclic benzene and borazole; noble gas clusters (Ng) n ; and others) are constrained inside the endohedral cavities of different O 4 nfullerene and fullerene like inorganic cages (С 60 , С 60 Н 36 , С 60 Н 24 , С 70 , С 84 , Al 20 О 30 , and others). The structure and properties of compressed L guests have been compared with the structure and properties of the same L molecules in the free state calculated at the same level of theory, in order to trace the changes in the molecular characteristics of L guests in going from the free state to the endohedral one.…”

“…According to calculations, all these clusters corre spond to local minima of the corresponding PESs (all vibrational frequencies are real). The repulsion between the closed electronic shells of the guests and cages [5][6][7][8][9][10][11] leads to contraction of the guest mole cules (the covalent bonds in them become a few hun dredths of an angstrom shorter). This contraction is accompanied by short wavelength shifts of the stretching vibration frequencies of these bonds on the order of a few hundreds of reciprocal centimeters, Abstract-The equilibrium geometries, normal mode frequencies, magnetic shielding constants, and ener getic characteristics of model endohedral 2(C 2 H 2 )@C 70 , (C 4 H 4 )@C 70 , 2(C 6 H 6 )C 84 , (C 12 H 12 )@C 84 , 6(CO)@C 84 , and (C 6 O 6 )@C 84 clusters, mimicking the structure and properties of the guest molecules under "ultrahigh" pressures inside the fullerene cages, were calculated at the density functional theory B3LYP/6 31G and B3LYP/6 31G* levels.…”

“…Many endoclusters considered in [5][6][7][8][9][10][11] are highly endothermic and can hardly be synthesized in the free state. Therefore, the calculations in [5][6][7][8][9][10][11] are model ones, and fullerene cages are considered as "high pressure nanoreactors" with different volumes and shapes of tight and extremely tight endohedral cavi ties.…”

“…Therefore, the calculations in [5][6][7][8][9][10][11] are model ones, and fullerene cages are considered as "high pressure nanoreactors" with different volumes and shapes of tight and extremely tight endohedral cavi ties. According to calculations, all these clusters corre spond to local minima of the corresponding PESs (all vibrational frequencies are real).…”