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Intersection, conical

Why has this, a slightly weird, coordinate system been chosen We see from the formula (6.43) for E+ and E- that f 1 and correspond to the fastest change of the first term and the second term under the square-root sign, respectively.  [Pg.262]

Any change of all other coordinates (being orthogonal to the plane 1 2) does not influence the value of the square root, i.e. does not change the difference between E+ and E- (although it changes the values of E+ andE-). [Pg.262]

Therefore, the hypersurface E+ intersects with the hypersurface E-, and their common part, i.e. the intersection set, are all those vectors of the n-dimensional space that fulfil the condition = 0 and (2 = 0- The intersection represents a (n — 2)-dimensional subspace of the n-dimensional space of the nuclear configurations. When we withdraw from the point (0,0, fa, 4. sN-e) by changing the coordinates f 1 and/or 2 a difference between E+ and E- appears. For small increments df j the changes in the energies E+ and E- are proportional to d i and for E+ and differ in sign. This means that the hypersurfaces E+ and E-as functions of f j (at 2 = 0 and fixed other coordinates) have the shapes shown in Fig. 6.14.a. For 2 the situation is similar, but the cone may differ by its angle. From this it follows that [Pg.262]

This is called the conical interseaion. Fig. 6.14.b. The cone opening angle is in general different for different values of the coordinates 3, 4. 3n-6 see Fig. 6.14.C. [Pg.263]

The conical intersection plays a fundamental role in the theory of chemical reactions (Chapter 14). The lower (ground-state) as well as the higher (exdted-state) adiabatic hypersurfaces are composed of two diabatic parts, which in polyatomics correspond to different patterns of chemical bonds. This means that the stem, (point) when moving on the ground-state adiabatic hypersurface towards the join of the two parts, passes near the conical intersection point and overcomes the energy barrier. This is the essence of a chemical reaction. [Pg.263]


Figure B3.4.16. A generic example of crossing 2D potential surfaces. Note that, upon rotating around the conic intersection point, the phase of the wavefunction need not return to its original value. Figure B3.4.16. A generic example of crossing 2D potential surfaces. Note that, upon rotating around the conic intersection point, the phase of the wavefunction need not return to its original value.
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... [Pg.2323]

Mead C A and Truhlar D G 1979 On the determination of Born-Oppenheimer nuclear motion wave functions including complications due to conical intersections and identical nuclei J. Chem. Phys. 70 2284... [Pg.2330]

Baer R, Charutz D M, Kosloff R and Baer M 1996 A study of conical intersection effects on scattering processes—the validity of adiabatic single-surface approximations within a quasi-Jahn-Teller model J. Chem. Phys. 105 9141... [Pg.2330]

The stoi7 begins with studies of the molecular Jahn-Teller effect in the late 1950s [1-3]. The Jahn-Teller theorems themselves [4,5] are 20 years older and static Jahn-Teller distortions of elecbonically degenerate species were well known and understood. Geomebic phase is, however, a dynamic phenomenon, associated with nuclear motions in the vicinity of a so-called conical intersection between potential energy surfaces. [Pg.2]

Molecular aspects of geometric phase are associated with conical intersections between electronic energy surfaces, W(Q), where Q denotes the set of say k vibrational coordinates. In the simplest two-state case, the W Q) are eigen-surfaces of the nuclear coordinate dependent Hermitian electronic Hamiltonian... [Pg.4]

Comparison between the first and last lines of the table shows that the sign of the ground-state wave function has been reversed, which implies the existence of a conical intersection somewhere inside the loop described by the table. [Pg.11]

While the presence of sign changes in the adiabatic eigenstates at a conical intersection was well known in the early Jahn-Teller literature, much of the discussion centered on solutions of the coupled equations arising from non-adiabatic coupling between the two or mom nuclear components of the wave function in a spectroscopic context. Mead and Truhlar [10] were the first to... [Pg.11]

Phase factors of this type are employed, for example, by the Baer group [25,26]. While Eq. (34) is strictly applicable only in the immediate vicinity of the conical intersection, the continuity of the non-adiabatic coupling, discussed in Section HI, suggests that the integrated value of (x Vq x+) is independent of the size or shape of the encircling loop, provided that no other conical intersection is encountered. The mathematical assumption is that there exists some phase function, vl/(2), such that... [Pg.13]

As mentioned in the introduction, the simplest way of approximately accounting for the geomehic or topological effects of a conical intersection incorporates a phase factor in the nuclear wave function. In this section, we shall consider some specific situations where this approach is used and furthermore give the vector potential that can be derived from the phase factor. [Pg.44]

Hence, the expression of Eq. (5) indicates that, in a polar coordinate system, Eq. (4) will remain unchanged even if the position of the conical intersection is shifted from the origin of the coordinate system. [Pg.46]

Single surface calculations with a vector potential in the adiabatic representation and two surface calculations in the diabatic representation with or without shifting the conical intersection from the origin are performed using Cartesian coordinates. As in the asymptotic region the two coordinates of the model represent a translational and a vibrational mode, respectively, the initial wave function for the ground state can be represented as. [Pg.47]

Single surface calculations with proper phase treatment in the adiabatic representation with shifted conical intersection has been performed in polai coordinates. For this calculation, the initial adiabatic wave function tad(9, 4 > o) is obtained by mapping t, to) ittlo polai space using the relations,... [Pg.48]

At this point, it is important to note that as the potential energy surfaces are even in the vibrational coordinate (r), the same parity, that is, even even and odd odd transitions should be allowed both for nonreactive and reactive cases but due to the conical intersection, the diabatic calculations indicate that the allowed transition for the reactive case ate odd even and even odd whereas in the case of nomeactive transitions even even and odd odd remain allowed. [Pg.51]

Reactive State-to-State Transition Probabilities when Calcnladons are Performed Keeping the Position of the Conical Intersection at the Origin of the Coordinates... [Pg.52]

Reactive State-to-State Transition ftobabilides when Calculations are Performed by Shifting the Position of Conical Intersection from the Origin of the Coordinate System... [Pg.52]

In Figure 1, we see that there are relative shifts of the peak of the rotational distribution toward the left from f = 12 to / = 8 in the presence of the geometiic phase. Thus, for the D + Ha (v = 1, DH (v, f) - - H reaction with the same total energy 1.8 eV, we find qualitatively the same effect as found quantum mechanically. Kuppermann and Wu [46] showed that the peak of the rotational state distribution moves toward the left in the presence of a geometric phase for the process D + H2 (v = 1, J = 1) DH (v = 1,/)- -H. It is important to note the effect of the position of the conical intersection (0o) on the rotational distribution for the D + H2 reaction. Although the absolute position of the peak (from / = 10 to / = 8) obtained from the quantum mechanical calculation is different from our results, it is worthwhile to see that the peak... [Pg.57]

The relative shift of the peak position of the rotational distiibution in the presence of a vector potential thus confirms the effect of the geometric phase for the D + H2 system displaying conical intersections. The most important aspect of our calculation is that we can also see this effect by using classical mechanics and, with respect to the quantum mechanical calculation, the computer time is almost negligible in our calculation. This observation is important for heavier systems, where the quantum calculations ai e even more troublesome and where the use of classical mechanics is also more justified. [Pg.58]

In this chapter, we discussed the significance of the GP effect in chemical reactions, that is, the influence of the upper electronic state(s) on the reactive and nonreactive transition probabilities of the ground adiabatic state. In order to include this effect, the ordinary BO equations are extended either by using a HLH phase or by deriving them from first principles. Considering the HLH phase due to the presence of a conical intersection between the ground and the first excited state, the general fomi of the vector potential, hence the effective... [Pg.79]

The ordinary BO approximate equations failed to predict the proper symmetry allowed transitions in the quasi-JT model whereas the extended BO equation either by including a vector potential in the system Hamiltonian or by multiplying a phase factor onto the basis set can reproduce the so-called exact results obtained by the two-surface diabatic calculation. Thus, the calculated hansition probabilities in the quasi-JT model using the extended BO equations clearly demonshate the GP effect. The multiplication of a phase factor with the adiabatic nuclear wave function is an approximate treatment when the position of the conical intersection does not coincide with the origin of the coordinate axis, as shown by the results of [60]. Moreover, even if the total energy of the system is far below the conical intersection point, transition probabilities in the JT model clearly indicate the importance of the extended BO equation and its necessity. [Pg.80]


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Adenine conical intersections

Anchor conical intersection

Chromophores conical intersections

Computational photochemistry conical Intersections

Conic intersections

Conic intersections nuclear wave function

Conic intersections overview

Conic intersections surface

Conic intersections symmetry approach

Conic intersections vector potentials

Conic/receiving slit intersection

Conical Intersections Topography

Conical intersection MECIs

Conical intersection accidental

Conical intersection control

Conical intersection displacement

Conical intersection excited-state reaction path

Conical intersection fractions

Conical intersection funnel

Conical intersection ground-state reaction path

Conical intersection hyperline

Conical intersection intermediates

Conical intersection location

Conical intersection of potential energy surfaces

Conical intersection optimization

Conical intersection photochemical funnel

Conical intersection photochemical reaction path

Conical intersection photoisomerization

Conical intersection reaction paths

Conical intersection research

Conical intersection singularity

Conical intersection structures

Conical intersection symmetry-allowed

Conical intersection, nonadiabatic coupling

Conical intersection, nonadiabatic quantum

Conical intersection, nonadiabatic quantum dynamics

Conical intersection, nonadiabatic quantum molecular systems

Conical intersections Hamiltonian equation

Conical intersections Jahn-Teller systems, Longuet-Higgins

Conical intersections Longuet-Higgins loops

Conical intersections Renner-Teller effect

Conical intersections adiabatic eigenstates

Conical intersections adiabatic representation

Conical intersections and intersystem crossings

Conical intersections and singlet-triplet

Conical intersections branching space

Conical intersections chemical reaction

Conical intersections coordinate origins

Conical intersections coordinates

Conical intersections decay

Conical intersections degeneracy

Conical intersections derivative coupling vector

Conical intersections derivative couplings

Conical intersections description

Conical intersections direct molecular dynamics, vibronic coupling

Conical intersections distribution solution

Conical intersections double-cone potential energy

Conical intersections dynamics

Conical intersections effective Hamiltonians

Conical intersections electronic states

Conical intersections elements

Conical intersections energy parameters

Conical intersections excited states

Conical intersections formulation

Conical intersections four-electron systems

Conical intersections geometric phase effect

Conical intersections geometric phase theory

Conical intersections gradient difference vector

Conical intersections ground state relaxation pathways

Conical intersections handling

Conical intersections intersection space

Conical intersections local topography

Conical intersections loop construction

Conical intersections minimal diabatic potential matrix

Conical intersections minimal models

Conical intersections molecular systems

Conical intersections multi-state effects

Conical intersections nonadiabatic effects

Conical intersections numerical calculations

Conical intersections orthogonal intersection adapted

Conical intersections pairing

Conical intersections parameters

Conical intersections pericyclic reactions

Conical intersections permutational symmetry

Conical intersections perturbation theory

Conical intersections phase

Conical intersections phase-change rule

Conical intersections photochemical systems

Conical intersections photochemistry

Conical intersections problem

Conical intersections repulsion

Conical intersections research background

Conical intersections seam loci

Conical intersections second-order degeneracy lifting

Conical intersections species

Conical intersections surfaces

Conical intersections systems

Conical intersections theoretical principles

Conical intersections three-electron systems

Conical intersections three-state molecular system

Conical intersections time-reversal symmetry

Conical intersections topologies

Conical intersections triatomic molecules

Conical intersections two-state systems

Conical intersections vibronic problem

Conical intersections, potential energy surfaces

Conical intersections, spin-orbit interaction

Conical intersections, spin-orbit interaction algorithms

Conical intersections, theoretical background

Conical intersections, two-state chemical

Conical intersections, two-state chemical reactions

Conicity

Cytosine conical intersections

Decay Paths from a Conical Intersection

Direct molecular dynamics conical intersections

Electronic Hamiltonian, conical intersections

Electronic Hamiltonian, conical intersections spin-orbit interaction

Elliptic conical intersection

Energy conical intersection

Extended conical intersection seam

Geometric phase effect adiabatic states, conical intersections

Gradient difference vector, direct conical intersections

Ground-state wave function conical intersections

HeH2 conical intersections

IRD from a Conical Intersection

Internal Conversion conical intersection

Intersect

Intersections of the Conic and Receiving Slit Boundary

Jahn-Teller effect conical intersection, adiabatic state

Jahn-Teller effect conical intersections

Locating conical intersections

Longuet-Higgins phase-change rule conical intersections

Minimal energy conical intersection

Minimum Energy Conical Intersection Optimization

Minimum-energy conical intersections

Minimum-energy conical intersections MECIs)

Molecular dynamics conical intersection location

Molecular orbital-conical intersection

Molecular systems conical intersection pairing

Molecular systems single conical intersection solution

Non-adiabatic coupling single conical intersection solution

Nonadiabatic effects from conical intersection

Noncrossing Rule and Conical Intersections

Nuclear dynamics adiabatic states, conical intersections

Nucleobases, conical intersections

Nucleobases, conical intersections cytosine

Nucleobases, conical intersections pyrimidine

Pauli principle conical intersections

Peaked conical intersections

Permutational symmetry adiabatic states, conical intersections

Photochemical reactions conical intersection, computational model

Polyatomic molecules and conical intersection

Potential energy surface conical intersection, nonadiabatic coupling

Reaction mechanisms conical intersections

Shift of conical intersection and replacement by avoided crossing

Sloped conical intersection

Special Topic 2.5 Conical intersections

Spin-Orbit Coupling and Conical Intersections

Spin-orbit coupling conical intersections

Spin-pairing conical intersection

Spin-pairing conical intersection location

Surface crossings conical intersection

Symmetry-required conical intersections

The Linear Model for Conical Intersection

Three state conical intersections

Three-electron conical intersections

Three-state molecular system, non-adiabatic noninteracting conical intersections

Thymine conical intersections

Triple conical intersection

Two-state molecular system, non-adiabatic single conical intersection solution

Uracil conical intersections

Vertical conical intersections

Wave function conical intersection

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