Potential energy surfaces 3-phospholene

Isomerization of 3-phospholene is of considerable interest for two reasons. First, the potential energy surface for the isomerization reaction coordinates is well known due to the spectroscopic studies of Harthcock and Laane [61,62]. Second, its Hamiltonian has important off-diagonal kinetic energy coupling terms, which provide a different test of the accuracy of the approximations used in the MRRKM theory than posed by previous applications. 

Let X be the ring-puckering coordinate and y the PH inversion coordinate in 3-phospholene (see Fig. 33). The dynamics of isomerization in this molecule is assumed to be adequately described by these coupled two DOF s without need for consideration of other DOFs. Under this assumption, the Harthcock-Laane potential energy surface consists of a fourth-order polynomial in x, a fourth-order polynomial in y, and a sixth-order polynomial coupling x and y. With molecular rotation neglected, the model Hamiltonian for 3-phospholene is given by... 

Figure 34. Contour plot of the potential energy surface for the isomerization of 3-phospholene. X is the ring pucking coordinate and y is the PH inversion coordinate. [From C. C. Marston and N. De Leon, J. Chem. Phys. 91, 3392 (1989).]...

The 3-phospholene potential energy surface has an energy barrier between isomers with height Ej, = 5083 cm. Results from direct trajectory calculations by De Leon and Marston [23,63] are available for one energy, namely, 5133 cm . The PSS for this energy is shown in Fig. 35. It is seen that although overall the system displays characteristics of chaotic motion, a considerable portion of the PSS supports quasi-periodic motion. 

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See also in sourсe #XX -- [ , , , , ]

See also in sourсe #XX -- [ , , , , ]

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