CAJ | 학술논문

用密度泛函方法(DFT)和全活化空间自洽场方法(CASSCF)以及耦合簇理论(CCSD)优化了反式和顺式HOOOH的平衡几何构型,用DFT计算了HOOOH顺反异构化反应的势能曲线和谐振动频率.用含时密度泛函理论(TD-DFT)和二阶全活化空间微扰理论(CASPT2)计算了反式和顺式HOOOH垂直激发能.计算结果表明:(1)反式异构体比顺式异构体稳定;(2)两种稳定构型的异构化反应有两种路径;(3)对于垂直跃迁能最低的单态和叁态,反式的垂直跃迁能比顺式的低;(4)在单激发态中,CASPT2方法预测的顺式HOOOH寿命最长的激发态为21A",其跃迁能是167.43 nm,寿命为1.44×10-5s;反式HOOOH寿命最长的激发态为21A,其跃迁能是165.52 nm,寿命为2.07×10-5 s.
용밀도범함방법(DFT)화전활화공간자흡장방법(CASSCF)이급우합족이론(CCSD)우화료반식화순식HOOOH적평형궤하구형,용DFT계산료HOOOH순반이구화반응적세능곡선화해진동빈솔.용함시밀도범함이론(TD-DFT)화이계전활화공간미우이론(CASPT2)계산료반식화순식HOOOH수직격발능.계산결과표명:(1)반식이구체비순식이구체은정;(2)량충은정구형적이구화반응유량충로경;(3)대우수직약천능최저적단태화참태,반식적수직약천능비순식적저;(4)재단격발태중,CASPT2방법예측적순식HOOOH수명최장적격발태위21A",기약천능시167.43 nm,수명위1.44×10-5s;반식HOOOH수명최장적격발태위21A,기약천능시165.52 nm,수명위2.07×10-5 s.
Equilibrium geometries of cis-HOOOH and trans-HOOOH have been investigated using the density functional theory (DFT), complete active space self-consistent-field (CASSCF), and coupled cluster with single and double replacement (CCSD) approaches. The harmonic vibrational frequencies on the optimized geometries were calculated using the DFT theory. The potential energy curve of the isomerization between the trans-HOOOH and cisHOOOH was obtained by DFT calculations. Time-dependent density functional theory (TD-DFT) and complete active space perturbation theory of second order (CASPT2) calculations have been performed to obtain the vertical excitation energies of selected low-lying singlet and triplet excited states. Computed results show that: (1) trans-isomer is more stable than cis-isomer; (2) there are two pathways of the conversion between the trans-HOOOH and cis-HOOOH; (3)the vertical excitation energies of the lowest singlet and triplet excited states in trans-HOOOH are lower than those in cis-isomer; (4) in the singlet excited states, 21A state in trans-HOOOH and 21A" state in cis-HOOOH have the longest lifetimes of 2.07×10-5 s and 1.44×10-5 s with the excitation energies of 165.52 and 167.43 nm, respectively.