Diabatic states

Sadygov R G and Yarkony D R 1998 On the adiabatic to diabatic states transformation in the presence of a conical intersection a most diabatic basis from the solution to a Poisson s equation. I J. Chem. Rhys. 109 20... 

As written, Eq. (52) depends on all the (infinite number of) adiabatic electi onic states. Fortunately, the inverse dependence of the coupling strength on energy separation means that it is possible to separate the complete set of states into manifolds that effeetively do not interact with one another. In particular, Baer has recendy shown [54] that Eq. (57), and hence Eq. (58) also holds in the subset of mutually coupled states. This finding has important consequences for the use of diabatic states explored below. 

Tbe model is that tbe ground-state PES is first altered by the electronic excitations (on-diagonal coupling leads to a change in equilibrium geomeby and frequency), and these smooth diabatic states are then further altered by vibronic (off-diagonal) coupling. 

The motivation comes from the early work of Landau [208], Zener [209], and Stueckelberg [210]. The Landau-Zener model is for a classical particle moving on two coupled ID PES. If the diabatic states cross so that the energy gap is linear with time, and the velocity of the particle is constant through the non-adiabatic region, then the probability of changing adiabatic states is... 

For example, there are also other approaches by Pacher et al. [106], Romero et al. [107], Sidis [40], and Domcke and Stock [42], which developed recipes for construction ab initio diabatic states. These methods can be efficient as long as one encounters, at nwst, one isolated conical intersection in a given region in... 

The physical meaning of B = mn is that no bifurcation into the diabatic state 3 > occurs at X2 on the second half of the sweep whatever the probability p2 is. The conditions of pi and C guarantee that the interference between 1 > and 2 > at Xi on the way back leads to the complete excitation to 2 >. The complete excitation to 3 > can be achieved by one period of sweeping, if we start from 0)2 The condition is given by... 

On the potential energy surfaces thus obtained 2D wavepacket dynamics calculations have been performed in the diabatic state representation. The reduced massses are regarded as those of CH2-ethylene system. The validity was examined by using on-the-fly ab initio molecular dynamics that were supplementarily performed. The dynamics calculations performed are composed of the following steps ... 

In the MOVB method, we use one Slater determinant with block-localized molecular orbitals to define individual VB configuration, called diabatic state. For example, the reactant state of the Sn2 reaction between HS- and CH3CI is defined as the Lewis bond structure of the substrate CH3CI ... 

The MOVB wave function for the adiabatic ground state is written as a linear combination of the diabatic states in Eqs. (4-11) and (4-12) ... 

While MOVB can yield reasonable energetic results and an excellent description of the overall potential energy surface on diabatic states and the adiabatic ground... 

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