With replacement of N atoms by CH groups in the most stable cycled N4H4 molecules,twelve possible isomers of Nn(CH)4-nH4 have been designed and optimized at the B3LYP/6-311++G level of theory.The vibrational frequenci...With replacement of N atoms by CH groups in the most stable cycled N4H4 molecules,twelve possible isomers of Nn(CH)4-nH4 have been designed and optimized at the B3LYP/6-311++G level of theory.The vibrational frequencies were calculated at the same level of theory.The structures and properties were analyzed with the natural bond orbital(NBO) and the atoms in molecules(AIM)theory.Meanwhile,the dipole moments and the energy have been discussed.The results indicate that stabilities of these isomers increase with more CH groups replacements of N4H4 due to decrements of their densities of energies.The G3B3 calculations show that the isomers have high heat of formations(HOFs)and higher density of energies,which indicate them maybe a kind of potential and novel energetic material.展开更多
The structural and electronic properties of (CdSe)_n(1≤n≤5) clusters are calculated using density functional theory within the pseudopotential and generalized gradient approximations. The calculated binding energies...The structural and electronic properties of (CdSe)_n(1≤n≤5) clusters are calculated using density functional theory within the pseudopotential and generalized gradient approximations. The calculated binding energies and highest occupied molecular orbital-lowest unoccupied molecular orbital gaps are compared with those obtained within local density approximation.展开更多
The equilibrium lattice parameters, electronic structure, bulk modulus, Debye temperature, heat capacity and Gibbs energy of TiB and TiB2 were investigated using the pseudopotential plane-wave method based on density ...The equilibrium lattice parameters, electronic structure, bulk modulus, Debye temperature, heat capacity and Gibbs energy of TiB and TiB2 were investigated using the pseudopotential plane-wave method based on density functional theory (DFT) and the improved quasi-harmonic Debye method. The results show that the total density of states (DOS) of TiB2 is mainly provided by the orbit hybridization of Ti-3d and B-2p states, and the total DOS of TiB is mainly provided by the hybrids bond of Ti-3d and B-2p below the Fermi level and Ti—Ti bond up to the Fermi level. The Ti—B hybrid bond in TiB2 is stronger than that in TiB. Finally, the enthalpy of formation at 0 K, heat capacity and Gibbs free energy of formation at various temperatures were determined. The calculated results are in excellent agreement with the available experimental data.展开更多
文摘With replacement of N atoms by CH groups in the most stable cycled N4H4 molecules,twelve possible isomers of Nn(CH)4-nH4 have been designed and optimized at the B3LYP/6-311++G level of theory.The vibrational frequencies were calculated at the same level of theory.The structures and properties were analyzed with the natural bond orbital(NBO) and the atoms in molecules(AIM)theory.Meanwhile,the dipole moments and the energy have been discussed.The results indicate that stabilities of these isomers increase with more CH groups replacements of N4H4 due to decrements of their densities of energies.The G3B3 calculations show that the isomers have high heat of formations(HOFs)and higher density of energies,which indicate them maybe a kind of potential and novel energetic material.
文摘The structural and electronic properties of (CdSe)_n(1≤n≤5) clusters are calculated using density functional theory within the pseudopotential and generalized gradient approximations. The calculated binding energies and highest occupied molecular orbital-lowest unoccupied molecular orbital gaps are compared with those obtained within local density approximation.
基金Project(07JJ3102)supported by the Natural Science Foundation of Hunan Province,ChinaProject(k0902132-11)supported by the Changsha Municipal Science and Technology,China
文摘The equilibrium lattice parameters, electronic structure, bulk modulus, Debye temperature, heat capacity and Gibbs energy of TiB and TiB2 were investigated using the pseudopotential plane-wave method based on density functional theory (DFT) and the improved quasi-harmonic Debye method. The results show that the total density of states (DOS) of TiB2 is mainly provided by the orbit hybridization of Ti-3d and B-2p states, and the total DOS of TiB is mainly provided by the hybrids bond of Ti-3d and B-2p below the Fermi level and Ti—Ti bond up to the Fermi level. The Ti—B hybrid bond in TiB2 is stronger than that in TiB. Finally, the enthalpy of formation at 0 K, heat capacity and Gibbs free energy of formation at various temperatures were determined. The calculated results are in excellent agreement with the available experimental data.
