TY - JOUR
T1 - Theoretical Study of HmGaPHn. Characteristics of Gallium - Phosohorus Multiple Bonds
AU - Dudley, Timothy J.
AU - Brown, William W.
AU - Hoffmann, Mark R.
PY - 1999/7/1
Y1 - 1999/7/1
N2 - Equilibrium structures, harmonic vibrational frequencies, and relative energies of 12 neutral or ionic gallium phosphorus hydrides are reported and analyzed. Hartree - Fock (HF), Becke's three-parameter exchange with Lee, Yang, and Parr correlation DFT (B3LYP), and second-order Møller-Plesset (MP2) calculations using the 6-311++G(d,p) basis set were performed on all molecules. Gallium-phosphorus bond energies were determined based on the MP2/6-311++G(d,p) calculations of the equilibrium structures and of their decomposition products. We find that the gallium-phosphorus double bond is, perhaps, surprisingly strong (i.e., 93 ± 2 kcal/mol) and short (2.128 ± 0.018 Å); CCSD(T)/6-311++G(3df,3dp) single-point calculations on HGaPH corroborate the prediction of a strong double bond. Bond order analysis of some of the neutral species revealed that these compounds satisfy a Pauling relation between bond length and bond order, and also bond energy and bond order. CASSCF(8|8) calculations on H2PGa show that the surprising weakness of the phosphorus-gallium bond in this compound can be understood in terms of an occupied antibonding a orbital. Comparisons of the B3LYP method to HF and MP2 methods reveal that the B3LYP DFT method, in most cases, gives relative energies and equilibrium structures in substantial agreement with the MP2 method for these types of compounds.
AB - Equilibrium structures, harmonic vibrational frequencies, and relative energies of 12 neutral or ionic gallium phosphorus hydrides are reported and analyzed. Hartree - Fock (HF), Becke's three-parameter exchange with Lee, Yang, and Parr correlation DFT (B3LYP), and second-order Møller-Plesset (MP2) calculations using the 6-311++G(d,p) basis set were performed on all molecules. Gallium-phosphorus bond energies were determined based on the MP2/6-311++G(d,p) calculations of the equilibrium structures and of their decomposition products. We find that the gallium-phosphorus double bond is, perhaps, surprisingly strong (i.e., 93 ± 2 kcal/mol) and short (2.128 ± 0.018 Å); CCSD(T)/6-311++G(3df,3dp) single-point calculations on HGaPH corroborate the prediction of a strong double bond. Bond order analysis of some of the neutral species revealed that these compounds satisfy a Pauling relation between bond length and bond order, and also bond energy and bond order. CASSCF(8|8) calculations on H2PGa show that the surprising weakness of the phosphorus-gallium bond in this compound can be understood in terms of an occupied antibonding a orbital. Comparisons of the B3LYP method to HF and MP2 methods reveal that the B3LYP DFT method, in most cases, gives relative energies and equilibrium structures in substantial agreement with the MP2 method for these types of compounds.
UR - http://www.scopus.com/inward/record.url?scp=0000352227&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0000352227&partnerID=8YFLogxK
U2 - 10.1021/jp9900133
DO - 10.1021/jp9900133
M3 - Article
AN - SCOPUS:0000352227
SN - 1089-5639
VL - 103
SP - 5152
EP - 5160
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
IS - 26
ER -