Bond dissociation energy lengths

Bond dissociation energy (D). 155 table of, 156 Bond length. 12 Bond strength, 11... 

Table 2. Singlet-triplet energy separations (AEsx) in M-H monomers, M—M bond dissociation energies (BDEs), SCF calculated bond lengths for the hypothetical, linear dimers HMMH (M = B, Al, Ga, In, or Tl) ...

Table 3. Bond lengths (A), bond dissociation energies (kcal/mol), a- and n-bond strengths (kcal/mol), charges on phosphorus (e), and orbital energies (eV) for first row transition metal complexes ML =PH ...

The relationships between bond length, stretching force constant, and bond dissociation energy are made clear by the potential energy curve for a diatomic molecule, the plot of the change in the internal energy AU of the molecule A2 as the internuclear separation is increased until the molecule dissociates into two A atoms ... 

Table 2. Bond dissociation energies D [kcal mol 1] at the computational level MP2/6-31G //HF/6-31G + ZPE bond lengths R [A] and wave numbers v [cm 1] of the stretching modes (HF/6-31G ).

Table 3.34. The Ar—F bond lengths R, average Ar—F bond-dissociation energies (BDE), and vibrational frequencies of ArF species...

The coordinate pertaining to solvent reorganization, z, is the same fictitious charge number as already considered in the Hush-Marcus model of outer-sphere electron transfer (Section 1.4.2), and so is the definition of 2q [equation (1.27)] and the difference between the Hush and Marcus estimation of this parameter. The coordinated describing the cleavage of the bond is the bond length, y, referred to its equilibrium value in the reactant, yRX. Db is the bond dissociation energy and the shape factor ft is defined as... 

The three parameters in the Morse function D, B, re are positive and are usually chosen to fit the bond dissociation energy, the harmonic vibrational frequency and the equilibrium bond length. At r = re, the Morse function V = 0. As r — D, V approaches D. For r re, V is large and positive, corresponding to short range repulsion. Although the Morse function has been used extensively, its representation of the potential away from re is not satisfactory. Several modifications have been proposed in Morse function. 

The yttrium monocarbide molecule was only recently observed under high resolution by Simard et al. (37) using Jet-cooled optical spectroscopy. The ground electronic state was determined to be an 0=5/2 state, which was consistent with the ab initio calculations of Shim et al. (38) who predicted a 11 ground state for YC in CASSCF calculations. The experimental work of Simard et al. yielded estimates for both the bond length and harmonic frequency of YC. In addition to their CASSCF calculations. Shim et al. (38) also reported results from mass spectrometric equilibrium experiments, which resulted in a bond dissociation energy of Do = 99.0 3.3 kcal/mol. The results from the present work are shown in Table I. An open-shell coupled cluster singles and doubles... 

Fig.1 The C-S bond dissociation energies and bond lengths for several model compounds, calculated assuming a hemolytic bond cleave...

Here, De is the bond dissociation energy, re is the equilibrium bond length, and a is a constant that characterizes the steepness of the potential and determines the vibrational frequencies. The advantage of using the Morse potential to improve upon harmonic-oscillator-level predictions is that its energy levels and wavefunctions are also known exactly. The energies are given in terms of the parameters of the potential as follows ... 

Molecule Electronic configuration Bond order Bond dissociation energy/kJ mol-1 Equilibrium bond length/pm... 

The variations in the bond dissociation energies of H2+, H2 and He.,+ and their equilibrium bond lengths are consistent with the expectations from molecular orbital theory. As the bond order increases it would be expected that the bonds formed would be stronger and shorter. 

The bond dissociation energies of H, and H2+ are 436 and 264 kJ mol, respectively. Correlate these data with the bond order of the species, and comment on the equilibrium bond lengths of 74 and 106 pm, respectively. 

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