More than ten years ago, the observation of low-energy structure in photoelectron energy spectrum, regarded as an “ionization surprise,” has overthrown our understanding strong-field physics. However, similar nuclear fragment generation from dissociating molecules upon photon absorption, one well-observed phenomena light-molecule interaction, still lacks unambiguous mechanism and remains myster...

The dissociative photoionization mechanism of internal energy selected C(2)H(3)F(+), 1,1-C(2)H(2)F(2)(+), C(2)HF(3)(+) and C(2)F(4)(+) cations has been studied in the 13-20 eV photon energy range using imaging photoelectron photoion coincidence spectroscopy. Five predominant channels have been found; HF loss, statistical and non-statistical F loss, cleavage of the C-C bond post H or F-atom migr...

In this study, the theoretical calculations of CO dissociation were carried out on Cu-Fe alloy surface by a full-potential method, which made more accurate results especially on the prediction of adsorption energies. This process may be governed by either a direct route or a H-assisted via HCO and COH intermediates pathways. In comparison to the pure surface Fe (100), the presence of Cu atom en...

The threshold photoelectron spectrum and threshold photoelectron-photoion coincidence spectra of CHCl2F, CHClF2 and CH2ClF are reported in the range 11.3-24.8 eV. Tunable photoionizing radiation with a resolution of 0.3 nm is provided from a synchrotron source with a vacuum-UV monochromator. The coincidence spectra are recorded continuously as a function of photon energy, allowing yields of the...

A new idea is brought in this paper that molecular dynamics with a force field integrated a brand new reactive potential form which considered bond breaking and forming can be used to simulate chemical reaction. As an example, we report here a force field CRACK developed for studying pyrolysis process of n-alkane. CRACK splines together a harmonic well and a shallow Lennard-Jones well: the harm...

We have investigated the electronic ground-state structure and binding mode of CH2N2 by ab initio multireference perturbation calculations CASPT2 and CASPT3, using correlation consistent cc-pVTZ basis sets. Our calculations suggest that the CH2-N2 binding between the CH2 (ãA1) and N2 (XΣg) moieties consists of a “harpooning” σ, bond from N2 to CH2 and a π-like bond due to the back-transfer of e...

The homolytic bond dissociation energy of the titanium neutral hydride D ‘(Ti-H) is determined experimentally for the first time by using guided ion beam tandem mass spectrometry to measure the kinetic energy dependence of the endothermic hydride abstraction reactions of Ti+ with methylamine, dimethylamine, and trimethylamine. From the thresholds of these reactions, the value of D ‘(Ti-H) = 2.1...

The nondynamical correlation energy may be defined as the difference between full configuration interaction within the space of all valence orbitals and a single determinant of molecular orbitals ~Hartree–Fock theory!. In order to describe bond breaking, diradicals, and other electronic structure problems where Hartree–Fock theory fails, a reliable description of nondynamical correlation is ess...

The present work provides a generalization of Mayer's energy decomposition for the density-functional theory (DFT) case. It is shown that one- and two-atom Hartree-Fock energy components in Mayer's approach can be represented as an action of a one-atom potential V(A) on a one-atom density rho(A) or rho(B). To treat the exchange-correlation term in the DFT energy expression in a similar way, the...

We study the dissociative dynamics of O2 on Ag(110) by performing classical and quasiclassical trajectory calculations on an adiabatic six-dimensional potential energy surface (PES). The PES is constructed from the interpolation of a large set of energies that are calculated using spin-polarized density functional theory. The minimum energy barrier to dissociation amounts to 0.36 eV. This value...