Ground potential energy surface

Figure 11. Contour plot of the adiabatic ground potential energy surface of the 2D model. The dashed line shows the seam surface. Taken from Ref. [27].

A and A = 0.1 eV. The adiabatic ground potential energy surface is shown in Fig. 11. The present results (solid line) are in good agreement with the quantum mechanical ones (solid circles). The minimum energy crossing point (MECP) is conventionally used as the transition state and the transition probability is represented by the value at this point. This is called the MECP approximation and does not work well, as seen in Fig. 10. This means that the coordinate dependence of the nonadiabatic transmission probability on the seam surface is important and should be taken into account as is done explicitly in Eq. (18). 

The first type, direct photodissociation, corresponds to the absorption of light that results in a direct transition from a bound molecule to photofragments. One deals here with a transition from a bound rovibrational state of the ground potential energy surface (pes) to an excited repulsive pes. 

Shepard interpolation has been applied to several systems. Wu et al. have used it to construct the ground potential energy surface for the reaction CH4 -I- H -> CH3 -I- H2 [63]. Neural networks can be described as general, non-linear fitting functions that do not require any assumptions about the functional form of the... 

Fig. 19 A graphical depiction of the variation in the energies of the upper (excited) and lower (ground) potential energy surfaces in normal-mode or g-space for the quadratic F (8) e JT problem. The origin corresponds to the system in its degenerate, high-symmetry configuration shown in Fig. 18...

Another route for accessing the ground potential energy surface at energies at or even above dissociation58 59 is via a nonradiative transition from an excited electronic state. One would then expect fluctuations in the lifetimes of the predissociating states much as the transition strengths fluctuate for the... 

Extraordinary Ground Potential Energy Surfaces Caused by Ionic Structures... 

We have shown above that when H2 interacts with nontransition metal atoms or diatoms such as Be, B, Be, Li or Be, volcanic ground potential energy surfaces (PES) are generated while an exceptional bond takes place. Rather than an ordinaiy dihydride with the simultaneous scission of the H2 bond, dihydrogen complexes are formed, e.g. Be [51. 

Gilibert, M., Aguilar, A., Gonzales, M., Mota, R Sayos, R. (1992). Dynamics of the N Su) + NO(X n) —> N2 (X E+) + OifPg) atmospheric reaction on the A" ground potential energy surface. 1. Analytical potential energy surface and preliminary quasiclassical trajectory calculation, /. Chem. Phys. 97 5542-5552. 

A fascinating but challenging issue in molecular reaction dynamics is the characterization of reactive resonances in elementary chemical reactions. Since Liu and co-workers experimentally demonstrated the existence of the reactive resonances in the polyatomic reactions of F -f CH4/CHD3/CD4, research interest on the polyatomic reaction of F -I- CH4 and its isotope variants has continued to grow. On the theoretical side and for understanding the reaction mechanism, some attention is focused on the construction of a 12-dimensional ground potential energy surface of the polyatomic system while some is on implementation of dynamical (both QCT and quantum) calculations. ... 

For too long we have stayed on the ground potential energy surface. Beginning with Chapter 7 we explore what can be learned and what can be done by taking advantage of electronically excited states. Experimentally this is made possible by the introduction of lasers. Theoretically this opens up new possibilities for the dynamics, including the option of the control of the collision. 

Light absorption leading to electronic excitation is commonly accompanied by radiative reemission as the electron decays back to the ground potential energy surface. However, in certain cases (dependent on excited-state radiative lifetime and potential features to be described below) the system returns to the ground electronic surface without optical emission, a so-called radiationless transition. Such non-radiative transition processes are important features of reaction pathways on both ground and excited surfaces. 

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