Phosphonates as mimics of phosphate biomolecules: ab initio calculations on tetrahedral ground states and pentacoordinate intermediates for phosphoryl transfer

1993 ◽  
Vol 58 (8) ◽  
pp. 2272-2281 ◽  
Author(s):  
Gregory R. J. Thatcher ◽  
A. Stewart Campbell
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Ground States ◽  
Phosphoryl Transfer

Ab initio calculations of infrared transition rates in the ground states of BF and BF+

1982 ◽  
Vol 92 (3) ◽  
pp. 250-256 ◽  
Author(s):  
Pavel Rosmus ◽  
Hans-Joachim Werner ◽  
Michael Grimm
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Ground States ◽  
Transition Rates

Accurate ab initio calculations of the ground states of FeC, FeC+, and FeC−

2010 ◽  
Vol 132 (19) ◽  
pp. 194312 ◽  
Author(s):  
Demeter Tzeli ◽  
Aristides Mavridis
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Ground States

The electronic structures, geometries, and relative energies of some N2H2 and N2H2+ systems

1977 ◽  
Vol 55 (2) ◽  
pp. 350-354 ◽  
Author(s):  
N. Colin Baird ◽  
David A. Wernette
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Configuration Interaction ◽  
Electronic Structures ◽  
Ground States ◽  
Heat Of Formation ◽  
Ionization Potentials ◽  
Basis Set ◽  
Relative Stabilities ◽  
Positive Ions

Ab initio calculations using the 4-31G basis set and extensive configuration interaction are reported for the 1Ag state of trans-diimide (1), the 3A″ and 1A1 states of 1,1-dihydrodiazine (2), and the ground states of the positive ions of these systems and of cis-diimide. In all cases the geometries have been optimized. The relative stabilities of these systems are discussed, with particular reference to the heat of formation of trans-1 and to the ionization potentials of 1 and 2.

Ab initio calculations of the electronic structure of the ground states of HBeHe+ and BeHe22+

2007 ◽  
Vol 442 (4-6) ◽  
pp. 194-200 ◽  
Author(s):  
Alister J. Page ◽  
David J.D. Wilson ◽  
Ellak I. von Nagy-Felsobuki
Keyword(s):  
Electronic Structure ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Ground States

scholarly journals Quantum-Chemical ab initio Calculations on the Three Isomers of Diborabenzene (C4H4B2)

2010 ◽  
Vol 65 (1-2) ◽  
pp. 113-122 ◽  
Author(s):  
Jaswinder Singh ◽  
Yuekui Wang ◽  
Gerhard Raabe
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Quantum Chemical ◽  
Ground States ◽  
Closed Shell ◽  
Triplet States ◽  
Structural Isomers ◽  
Carbon Carbon Bond ◽  
Lowest Unoccupied Molecular Orbitals ◽  
Effective Stabilization

AbstractQuantum-chemical ab initio calculations up to the ZPE+CCSD(T)/aug-cc-pVTZ//MP2/6- 311++G** level were performed on three possible structural isomers of diborabenzene (C4H4B2). All three molecules were found to be local minima on the C4H4B2 energy surface and to have closed shell singlet ground states. While the ground states of the 1,3- and 1,4-isomer are planar and of C2v and D2h symmetry, respectively, 1,2-diborabenzene is non-planar with a C2 axis passing through the center of the BB bond and the middle of the opposite carbon-carbon bond as the only symmetry element. The energetically most favourable 1,3-diborabenzene was found to be about 19 and 36 kcal/mol lower in energy than the 1,2- and the 1,4-isomer. Planar 1,3- and 1,4-diborabenzene have three doubly occupied π orbitals while non-planar 1,2-diborabenzene has also three doubly occupied orbitals which can be derived from the π orbitals of its 3.7 kcal/mol energetically less favourable planar form (“π-like” orbitals). The lowest unoccupied orbitals of all three isomers have σ symmetry with large coefficients at the two boron atoms. These orbitals are lower in energy than the lowest unoccupied molecular orbitals (LUMOs) of e. g. benzene and pyridine and might cause pronounced acceptor properties which could be one of the reasons for the elusiveness of the title compounds. The results of bond separation reactions show that cyclic conjugation stabilizes all three diborabenzenes relative to their isolated fragments. The most effective stabilization energy of about 24 kcal/mol was found for the energetically lowest 1,3-isomer. This value amounts to approximately one third of the experimental value for the bond separation energy of pyridine. In all cases the energetically lowest triplet states are significantly (16 - 24 kcal/mol) higher in energy than the singlet ground states. Also among the triplets the 1,3-isomer is the energetically most fabourable species.

Ab initio calculations for ground states of CH2Li? and CH2Be

1974 ◽  
Vol 36 (2) ◽  
pp. 103-108 ◽  
Author(s):  
Ugo Lamanna ◽  
Marco Maestro
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Ground States

Accurate ab initio calculations for the ground states of N2, O2 and F2

1987 ◽  
Vol 135 (6) ◽  
pp. 543-548 ◽  
Author(s):  
Stephen R. Langhoff ◽  
Charles W. Bauschlicher ◽  
Peter R. Taylor
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Ground States

Millimetre-wave and infrared spectroscopy of Br13 CN: anharmonic force field of cyanogen bromide from spectroscopic data and ab initio calculations

1997 ◽  
Vol 90 (3) ◽  
pp. 495-497
Author(s):  
CLAUDIO ESPOSTI ◽  
FILIPPO TAMASSIA ◽  
CRISTINA PUZZARINI ◽  
RICCARDO TARRONI ◽  
ZDENEK ZELINGER
Keyword(s):  
Infrared Spectroscopy ◽  
Force Field ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Spectroscopic Data ◽  
Cyanogen Bromide ◽  
Millimetre Wave ◽  
Anharmonic Force
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