Spin-flip reactions of Zr + C2H6 researched by relativistic density functional theory
Density functional theory (DFT) with relativistic corrections of zero-order regular approximation (ZORA) has been applied to explore the reaction mechanisms of ethane dehydrogenation by Zr atom with triplet and singlet spin-states. Among the complicated minimum energy reaction path, the available states involves three transition states (TS), and four stationary states (1) to (4) and one intersystem crossing with spin-flip (marked by a double dagger'): (3) Zr + C (2) H (6) -> (3) Zr-CH (3) -CH (3) ( (3) 1) -> (3) TS (1/2) -> (3) ZrH-CH (2) -CH (3) ( (3) 2) -> (3) TS (2/3) aY(1) (1) ZrH2-CH2 = CH2 ( (1) 3) -> (1) TS (3/4) -> (1) ZrH (3) -CH = CH (2) ( (1) 4). The minimum energy crossing point is determined with the help of the DFT fractional-occupation-number (FON) approach. The spin inversion leads the reaction pathway transferring from the triplet potential energy surface (PES) to the singlet's accompanying with the activation of the second C-H bond. The overall reaction is calculated to be exothermic by about 231 kJ mol(-1). Frequency and NBO analysis are also applied to confirm with the experimental observed data.
potential energy surface dft fractional occupation number approach minimal energy crossing point spin-flip transitions zirconium and ethane reaction mechanism