微小圆管中分裂火焰的实验与理论研究

对丙烷/空气在内径2 mm的圆管内的预混燃烧进行了实验研究,借助于高速数码摄像机发现了分裂火焰现象,其中一个为向上游传播的较亮的常规火焰,另一个为向下游传播的较暗的微弱火焰。这些火焰先后熄灭,经过一段时间后又重复发生自着火、分裂、反向传播、灭火过程。这种现象在富燃、化学恰当比以及贫燃火焰中都有存在。一维非稳态计算表明化...     

CASSCF calculations of triplet state properties: applications to benzene derivatives

We illustrate the capability of the complete active space self-consistent field method by Roos and co-workers for calculations of triplet state properties. We report phosphorescence lifetimes, zero-field splitting parameters, and nuclear quadrupole coupling constants for the lowest triplet state of a variety of benzene derivatives.     

Fine and hyperfine structure in three low-lying 3Σ+ states of molecular hydrogen

The fine structure constant (electron spin-spin coupling) and the hyperfine structure parameters (electron-nuclear spin coupling, including spin-rotation and electron-nuclear quadrupole coupling) in the low-lying triplet states b³Σ⁺ _u, a³Σ⁺ _g and e³Σ⁺ _u of molecular hydrogen and deuterium are calculated using a recently developed technique with full configuration interaction and multiconfiguration self-consistent field wave functions. The second-order spin-orbit coupling contribution to the ³Σ⁺ states splitting is negligible, and the calculations therefore provide a good estimate of the zero-field splitting based only on the electron spin-spin coupling values. For the bound a³Σ⁺ _g state a negligible zero-field splitting is found, in qualitative agreement with the e-a spectrum. The zero-field splitting parameter is considerable for the repulsive b³Σ⁺ _u state (?1 cm^?1) and of intermediate size for the bound e³Σ⁺ _u state. The isotropic hyperfine coupling constant is very large not only for the valence b³Σ⁺ _u state (1580 MHz) but also for the Rydberg a and e triplet states (?1400 MHz). The quadrupole coupling constants for the deuterium isotopes are negligible (0.04–0.07 MHz) for all studied triplet states. The electric dipole activity of the spin sublevels in the triplet-singlet transitions to the ground state is estimated by means of the quadratic response technique.