Ruozhuang Liu

Theoretical study of structures and energies of [HCOO]+ and [COOH]+ and their rearrangement

Abstract The structures of [HCOO] + , [COOH] + and the transition state on the rearrangement path are obtained by the MC SCF gradient method with a 6-31G ★ basis set. The energy barrier of the singlet rearrangement reaction, 8.47 kcal mol , calculated by the MC SCF MRSDQ CI method with a 6-311G ★★ basis set suggests that [HCOO] + is a stable biradical and experimentally observable.

Structures and stabilities of C60-rings

Abstract A method to construct various C60-rings is given. 36 C60-rings with D n h and C n v symmetries have been investigated using self-consistent-field molecular orbital method. Their stabilization energies (E) are mainly affected by the distortion of the C60 balls (σ), the number of double bonds introduced into pentagons per C60 (j) and the number of formed intermolecular bonds (k). Their electronic properties are discussed and compared with those of single C60.

Theoretical study on unimolecular reactions of formyl cyanide

Abstract The possible unimolecular reactions of formyl cyanide (CHOCN) in its ground state have been investigated with ab initio method, at the level of MP4 (SDTQ)/6-31G * //HF/6-31G * . Our theoretical analysis indicated that in the case of unimolecular reaction pathways, CHOCN is rather stable at room temperature. However, at higher temperature this compound can decompose into HCN and CO. All of these are in agreement with the experimental identifications.

Electronic properties of one-dimensional C36 polymers

Electronic structures for several neutral and anionic one-dimensional (1D) C36 polymers are investigated by using the ab initio self-consistent-field crystal orbital method based on the B3LYP (Becke–Lee–Yang–Parr) density functional theory. Calculations show that all the neutral polymers are semiconductors with energy gaps in the range from 0.55 to 2.04 eV. The possibilities of superconducting and Peierls phase transitions are also explored for these metallic anionic polymers at the same time. It is found that the intramolecular electron–phonon (e–p) coupling in metallic 1D C36 polymers plays an important role in producing high superconducting transition temperatures (Tc). The estimated Peierls phase transition temperatures (Tp) are very small due to the very weak intermolecular e–p interactions.

Structures and stabilities of C36-rings

Abstract C36-rings with Dnh symmetries have been investigated using the semi-empirical molecular orbital method (AM1). The ring structures are beneficial to the stability of the C36 systems. An analysis of several factors, such as the change in strain energies due to the distortion of C36 cages, the type of the bonded carbon atoms, the size of retained aromatic domains and the shared pentagon–pentagon double bonds, is given for their contributions to stabilities of the C36-rings. The electronic properties are also discussed and compared with those of C60-rings.

Theoretical study on the dynamic properties and state-selected rate constants of the reaction CH(4Σ−)+H2→CH2(3B1)+H

Abstract The reaction path of the reaction CH ( 4 Σ − )+H 2 →CH 2 ( 3 B 1 )+H has been traced by Fukuis theory of intrinsic reaction coordinate using an ab initio MO method with the gradient technique. Furthermore, the dynamical properties along the reaction path and CVT rate constants with correction of tunneling effect and effect of curvature have been investigated by reaction path Hamiltonian theory and variational transition state theory. On this basis, the adiabatic and diabatic vibrational-state-selected rate constants were calculated. The results show that the effects of CVT method are notable, and the rate enhancement is also notable while the H 2 stretching mode is vibrationally excited.

Electronic structures and infrared spectra of C120O2, C120OS and C120S2

Electronic structures and infrared spectra of C120XY molecules (X, Y=O, S) and some of the corresponding ions are investigated using PM3 semi-empirical molecular orbital calculations with full optimization of geometrical structures. It is found that the energy penalty is about 30–42 kJ/mol due to introducing a double bond in the fivemembered ring except for C120O2− and triplet C120O22−. It is also found that the structures of neutral molecules and the corresponding ions are almost the same; for instance, the change of bond length is less than 0.001 nm. The change of frontier orbits from oxide to sulfide is little as well. The triplet states of C120O22− and C120OS2− are more stable than their singlet states, which means that C120O22− and C120OS2− follow the Hund’s rule. The vibration analysis showed that the infrared spectra of neutral C120O2 and C120OS molecules are in good agreement with the experimental results. Compared with the neutral molecule, vibration frequencies of triplet C120O22− change little, but the vibration intensities are enhanced obviously.