TY - JOUR
T1 - Theoretical study on structures and stability of SiaPa isomers
AU - Huang, Xu Ri
AU - Ding, Yi Hong
AU - Li, Ze Sheng
AU - Sun, Chia Chung
PY - 2000/9/28
Y1 - 2000/9/28
N2 - The structures, energetics, spectroscopies, and isomerization of possible low-lying Si2P2 isomers in both singlet and triplet states are theoretically investigated at the B3LYP/6-31 IG(d) and CCSD(T)/6-31 l+G(2df) (single-point) levels. At the final CCSD(T)/6-311+G(2df)//B3LYP/6-311G(d) level, the lowest energy isomer is a singlet butterfly-like SiPSiP structure 11 with P-P cross bonding followed by a singlet rhombic SiPSiP isomer 12 with Si-Si cross bonding, whereas the cyanogen analogue PSiSiP 15 is the highest lying of all the singlet isomers. The singlet potential energy surface of Si2P2 indicates that the rhombic isomer 12 is kinetically much more stable than the butterfly-like isomer 11, although isomer 12 is 3.2 kcal/mol higher in energy than isomer 'l, while other isomers are kinetically unstable toward isomerization to isomer 11 or 12. It is also shown that the triplet SI2P2 isomers are energetically higher than all the single species except 15. Furthermore, for the most relevant singlet Si2P2 isomers and interconversion transition states, the relative energies obtained at the B3LYP/6-31 IG(d) level are in excellent agreement with the values calculated at the single-point CCSD-(T)/6-311+G(2df) level within 2 kcal/mol. Finally, the structural, energetic and kinetic similarities and discrepancies between the isomers of Si2P2 and other analogous molecules C2N2, SI2N2 and C2?2 are compared and analyzed.
AB - The structures, energetics, spectroscopies, and isomerization of possible low-lying Si2P2 isomers in both singlet and triplet states are theoretically investigated at the B3LYP/6-31 IG(d) and CCSD(T)/6-31 l+G(2df) (single-point) levels. At the final CCSD(T)/6-311+G(2df)//B3LYP/6-311G(d) level, the lowest energy isomer is a singlet butterfly-like SiPSiP structure 11 with P-P cross bonding followed by a singlet rhombic SiPSiP isomer 12 with Si-Si cross bonding, whereas the cyanogen analogue PSiSiP 15 is the highest lying of all the singlet isomers. The singlet potential energy surface of Si2P2 indicates that the rhombic isomer 12 is kinetically much more stable than the butterfly-like isomer 11, although isomer 12 is 3.2 kcal/mol higher in energy than isomer 'l, while other isomers are kinetically unstable toward isomerization to isomer 11 or 12. It is also shown that the triplet SI2P2 isomers are energetically higher than all the single species except 15. Furthermore, for the most relevant singlet Si2P2 isomers and interconversion transition states, the relative energies obtained at the B3LYP/6-31 IG(d) level are in excellent agreement with the values calculated at the single-point CCSD-(T)/6-311+G(2df) level within 2 kcal/mol. Finally, the structural, energetic and kinetic similarities and discrepancies between the isomers of Si2P2 and other analogous molecules C2N2, SI2N2 and C2?2 are compared and analyzed.
UR - http://www.scopus.com/inward/record.url?scp=0034726886&partnerID=8YFLogxK
U2 - 10.1021/jp000979a
DO - 10.1021/jp000979a
M3 - Article
AN - SCOPUS:0034726886
SN - 1089-5639
VL - 104
SP - 8765
EP - 8772
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
IS - 38
ER -