Intrinsic Reaction Coordinate Calculations for Very Flat Potential Energy Surfaces: Application to Singlet Sl2H2 Isomerization

摘要

Silasilene is an important species that may appear in the chemical vapor deposition of silicon. This paper reports an intrinsic reaction coordinate (IRC), or a minimum energy path (MEP), of the isomerization from silasilene to bridged disilyne obtained by using the local cubic and quadratic approximations. These new approximations generate a correct IRC for this isomerization, while some conventional methods fail to predict a reasonable IRC because of the very flat potential energy surface. This reaction path bifurcates to two identical IRCs to reach bridged disilyne. The activation energy for this isomerizations is predicted to be less than 3 kcal/mol. This energy barrier may disappear at high temperatures. The paper also compares the IRCs on the simple potential energy surfaces of the ammonia inversion and the hydrogen cyanide isomerization generated by using the local cubic and quadratic approximations with those obtained by some conventional methods. Reprints. (AW)