Topological effects in low-lying electronic states of linear N2H2 + and HBNH+ associated with onset of bending
TL;DR: In this paper, the authors investigated the topological effects of Renner-Teller conical interactions in slightly bent N2H2+ and HBNH+ and found that the appearance of JT-CIs is in molecular plane while for N 2H2+, in certain nonplanar configuration, in sharp contrast to th...
Abstract: The current decade has seen illuminating and extensive study of interplay of topological effects such as Renner–Teller and Jahn–Teller (JT) effects in small molecules. Study of such effects in HCNH molecule showed an interesting feature that for slightly bent system, a pair of JT conical interactions (CIs) appear only for certain nonplanar configuration, in contrast to its appearance in CS configuration (molecular plane) for C2H2+. Moreover, since the feature of appearance of JT-CIs in two 2Σ+ states of HCNH in some bent configuration may be critically associated to the abundance of HNC in interstellar spaces, as advocated recently by Das and Mukhopadhyay (J. Phys. Chem. 117, 8680 (2013)), the interest in such topological studies have remained relevant. In this article we have investigated such topological effects for slightly bent N2H2+ and HBNH+. Interestingly, the appearance of JT-CIs are, for HBNH+, in molecular plane while for N2H2+, in certain nonplanar configuration, in sharp contrast to th...
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TL;DR: In this article, the authors investigate the relationship between JTCI and RTPI in the linear tetra-atomic molecular system with slightly bent HCNOplus, a motivated choice of tetraatomic with all four different atoms.
Abstract: Search for configuration space with welldefined topological (Berry) phases corresponding to Jahn Teller (JT) conical intersection (CI) and Renner Teller(RT) parabolic intersection (PI) in the linear tetra-atomic molecular system on introduction of bending, reveal the interesting aspect that these potential intersections may appear in molecular plane as well as out of the molecular plane. While understanding this aspect is important for following the class of phenomena led by potential intersections, till date studies on molecular systems including pairs like (C2H2plus , HCNH) as well as (N2H2plus , HBNHplus ), have not been able to clarify the issue. The present paper embodies calculation of non-adiabatic coupling terms (NACTs) involving four low lying states of slightly bent HCNOplus , a motivated choice of tetra-atomic with all four different atoms, to study this aspect associated with JTCI and RTPI in slightly bent linear system. The plane of appearance of these effects, has been advocated to be related to electronic configuration of the concerned states of the molecular system.
TL;DR: In this paper, the authors investigate the relationship between JTCI and RTPI in the linear tetra-atomic molecular system with slightly bent HCNOplus, a motivated choice of tetraatomic with all four different atoms.
Abstract: Search for configuration space with welldefined topological (Berry) phases corresponding to Jahn Teller (JT) conical intersection (CI) and Renner Teller(RT) parabolic intersection (PI) in the linear tetra-atomic molecular system on introduction of bending, reveal the interesting aspect that these potential intersections may appear in molecular plane as well as out of the molecular plane. While understanding this aspect is important for following the class of phenomena led by potential intersections, till date studies on molecular systems including pairs like (C2H2plus , HCNH) as well as (N2H2plus , HBNHplus ), have not been able to clarify the issue. The present paper embodies calculation of non-adiabatic coupling terms (NACTs) involving four low lying states of slightly bent HCNOplus , a motivated choice of tetra-atomic with all four different atoms, to study this aspect associated with JTCI and RTPI in slightly bent linear system. The plane of appearance of these effects, has been advocated to be related to electronic configuration of the concerned states of the molecular system.
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TL;DR: The Born-Oppenheimer treatment leads to the adiabatic-to-diabatic framework where the non-adiabatic terms are the physical entities responsible for the coupling as mentioned in this paper.
259 citations
TL;DR: In this article, the Born-Oppenheimer approximation for separating nuclear and electronic motion can be adapted to a degenerate electronic state, and the Jahn-Teller effect can be set up in their simplest form using vibrational amplitudes associated with special linear combinations of the degenerate wave functions.
Abstract: The first part of this paper shows how the ordinary Born‐Oppenheimer approximation for separating nuclear and electronic motion can be adapted to a degenerate electronic state. To set up equations of motion for the dynamical Jahn‐Teller effect in their simplest form we use vibrational amplitudes associated with special linear combinations of the degenerate electronic wave functions, chosen to vary as slowly as possible with nuclear displacements. We also discuss briefly the symmetry‐forbidden electronic transitions allowed by a Jahn‐Teller distortion. In the second we make molecular orbital calculations of the energies and distorted shapes of some aromatic hydrocarbon molecules. The differences in energy between the distorted and symmetrical shapes (in kcal/mole) are cyclobutadiene 11.43; cyclopentadienyl 1.414, cycloheptatrienyl 0.859; benzene negative ion 1.077; triphenylene and coronene negative ions 0.385 and 0.299. In the last three each shape of minimum energy is separated from two equivalent ones by a small potential barrier, respectively, 0.000, 0.001, and 0.002. The ground state of each radical is doubly degenerate, and it can oscillate about a continuous series of distorted shapes. In the excited 1E1u+ and 3E1u+ states of benzene the distortions are much smaller, and the CC bonds probably bend rather than stretch.
178 citations
TL;DR: In this paper, the general adiabatic-diabatic transformation matrix is derived from the non-adiabatic transition matrix, and the transition matrix can be expressed as
Abstract: (1980). Electronic non-adiabatic transitions derivation of the general adiabatic-diabatic transformation matrix. Molecular Physics: Vol. 40, No. 4, pp. 1011-1013.
150 citations
TL;DR: In this paper, a known method for treating reactive systems on a single surface is first given, and then it is shown how to proceed to include electronically nonadiabatic effects, and the final equations are very similar to those of the one surface case and, therefore, existing methods for treating the single surface case can be directly applied to the many surface case.
Abstract: Electronic nonadiabatic interactions are smoothly incorporated into existing exact quantum mechanical methods for treating reactive (or nonreactive) bimolecular systems. A known method for treating reactive systems on a single surface is first given, and then it is shown how to proceed to include electronically nonadiabatic effects. The unexpected result is that the final equations are very similar to those of the one surface case and, therefore, existing methods for treating the single surface case can be directly applied to the many surface case. For the sake of simplicity the study is performed in the frame of the collinear model, but the treatment can easily be extended to three dimensional systems.
145 citations
TL;DR: In this article, it was shown that conical intersections are much more likely than local minima of the electronic energy gap to be associated with the neighborhood of a conical intersection than with an avoided intersection.
Abstract: We prove that conical intersections are much more likely than local minima of the electronic energy gap. Therefore, if one encounters a very small electronic energy gap along a path through configuration space, it is much more likely to be associated with the neighborhood of a conical intersection than with an avoided intersection.
117 citations