Ab initio potential curves

Fig. 39. Calculated spin-orbit splitting in the state of O2 as a function of the vibrational quantum numbers by employing the matrix element displayed in Fig. 38. Curve A rrfers to the calculation that employs the ab initio potential curve for vibrational averaging B employs the experimental RKR curve for vibrational averaging, and C shows the experimental points from various measurements.

J. S. Wright and R. J. Williams,/. Chem. Phys., 78,5264 (1983). Accurate Ab Initio Potential Curves Using Bond Functions. 

This system was artificially modeled based on the ab initio potential curves of LiH molecule. [493] The spatial distribution of the nonadiabatic coupling element is superposed on the two potential curves. In this system,... 

Sherrill CD et al (2009) Assessment of standard force field models against high-quality ab initio potential curves for prototypes of pi-pi, CH/pi, and SH/pi interactions. J Comput Chem 30 2187-2193... 

An example of a potential energy fiinction based on all these ideas is provided by the 10-parameter fiinction used [88] as a representation of ab initio potential energy curves for Fle-F and Ne-F ... 

Figure 47. Ab initio potential energy curves of the HI molecule. The unit of y axis is reaprocal centemeters.

Fig. 13.5 Ab initio potential energy curves for cc-pVQZ/TZ UCCSD(T) bottom cc-pVQZ/TZ the C" (planar) fragmentation of a 3A" ketene, UCCSD(T) + cc-pV5Z MP2 basis set and...

It thus appears that a judicious application of correction curves of the form of (III.l) can transform a uniform set of ab initio potential-energy curves into a set of corrected curves that are very representative of the actual system. Such curves must be of similar chemical character such as all valence states or all Rydberg states. Rydberg-valence mixing cannot be easily accounted for in ab initio calculations, and simple empirical corrections do not seem possible for such situations. 

Bussery-Honvault B, Moszynski R (2006) Ab initio potential energy curves, transition dipole moments, and spin-orbit coupling matrix elements for the first twenty states of the calcium diatom. Mol Phys 104 2387-2402... 

Fig. 1. Ab initio potential energy curves for O, ()u, and 1 states of Tl2, with 3 g, 3IIU, and Ig curves (computed without spin-orbit coupling) for comparison.

Values of the F , Fm, and Fm force constants are determined from an ab initio potential energy curve calculated as a function of displacements of the local mode coordinate from equilibrium. The potential energy curves extend from —0.2 A to... 

Fig. 7. Diabatic ab initio potential energy curves for 1 + O2. These calculations correspond to a fixed 0-0 distance of 2.287 bohr and a Jacobi angle of 50°.

Fig. 6. Free energy (at zero pressure) for a-nitrogen and /3-nitrogen, in different mean field models (closed lines). The dashed free rotor curve has been calculated from the isotropic (/, 12, ly) - (0,0, 0) term of the ab initio potential by adding the free rotor expression for the free energy. The dashed jump model curve has been obtained from the localized mean field solution (with the full anisotropic potential) by adding an entropy term -kBT In 6 (see the text).

Fig. 18.—Torsional Potential of the Exocyclic C-O Bond in the Axial Form of 2-Methox-yoxane Calculated by the PCILO Method (Full Line) and Corresponding Potential in Dimeth-oxymethane (Dashed Line) Calculated by the CNDO/2 Method (Curve a) and by the ab initio Method (Curve b). ...

Figure 16, Ab initio potential energy curves for HeJ -CeFe and a few low lying He2 + C6F6 states obtained in a parallel theoretical approach.

Figure 25. Ab initio potential energy curves for CH3S in symmetry plotted as a function of the CH3-S distance. Taken from ref. 58.

Ab Initio Calculations. To gain some insight about the photodissociation process of HS, we show in Figure 27 the ab initio potential energy curves calculated by Bruna and Hirsch [144] as a function of the H-S distance [r(H-S)] in atomic units (Bohr radius = Og). The HS( E ) and HS( A) potential curves are repulsive and correlate asymptotically to the formation... 

Helhnann R, Bich E, Vogel E (2007) Ab initio potential energy curve for the helium atom pair and thermophysical properties of dilute helium gas. I. Helium-helium interatomic potential. Mol Phys 105 3013-3023... 

Figure 24.16 Ab initio potential of the C---F coordinate in the ground and excited states. Notice the energy barrier in both X and A potential curves as the C—F distance increases. Adapted from Stert et al, Phys. Chem. Chem. Phys., 2001, 3 3939, with permission of the PCCP Owner Societies... 

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