Hydrogen bond in FH…FM (M = Li, Na, K) dimers: Nonempirical calculations

Minyaev, R. M.; Getmanskii, Iliya V.; Starikov, А. G.

doi:10.1134/s0036024407070163

Cited by 11 publications

(21 citation statements)

References 11 publications

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“…The dynamics of these reactions is not mediated by a single conventional TS associated with an SP of index one. [7,[11][12][13][35][36][37][38][39][40] For this reason it is important to have a method that explores a region of a PES where an SP 2 emerges. The GAD method is a potential algorithm to be used for this aim.…”

Section: Search Of Sp's Of Higher Index By Gad Trajectoriesmentioning

confidence: 99%

Embedding of the saddle point of index two on the PES of the ring opening of cyclobutene

Quapp

Bofill

2015

Int. J. Quantum Chem.

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The ring opening of cyclobutene is characterized by a competition of the two different pathways: a usual pathway over a saddle of index one (SP 1 ) along the conrotatory behavior of the end groups, as well as a "forbidden" pathway over a saddle point of index two (SP 2 ) along the disrotatory behavior of the end CH 2 groups. We use the system of ordinary differential equations for the method of the gentlest ascent dynamics (GAD) to determine saddle points of the potential energy surface (PES) of the ring opening of cyclobutene to cis-butadiene. We apply generalized GAD formulas for the search of a saddle point of index two. To understand the relation of the different regions of the PES (around minimums, around SPs of index one or two) we also calculate valley-ridge inflection (VRI) points on the PES using Newton trajectories (NT). VRIs and the corresponding singular NTs subdivide the regions of "attraction" of the different SPs. We calculate the connections of the SP 2 (in its different symmetry versions) with different SPs of index one of the PES by different "reaction pathways." We compare the possibilities of the tool of the GAD curves for the exploration of PESs with these of NT. The barrier of the disrotatory SP 2 is somewhat higher than the barrier of the conrotatory SP 1 , however, pathways across the slope to the SP 2 open additional reaction valleys. IntroductionMathematics has had a profound impact on science, providing a means to understand the world around us in unprecedented ways.[1] With the advantage of the computer age, the subject of modelization has hugely grown in importance. In particular, over the last decades significant advances in our understanding of the world of chemistry have culminated in the development of a very large set of concepts. Some of these concepts are the potential energy surface (PES) [2][3][4] and the chemical reaction path (RP) [5] being the basic concepts for the theories of chemical dynamics and chemical transformations. The PES is a continuous function of the coordinates of the nuclei over an IR N , thus it is an N-dimensional hypersurface. It should have continuous derivatives of at least second order for our treatments. If Cartesian coordinates are used, then N53 n, however, we may also use N53 n26 nonredundant, internal coordinates for an n-atomic molecule. The PES can be seen as formally divided in catchments associated with local minima.[2] For such a picture, one has in mind steepest descent (SD) curves. The first order saddle points or transition states (TSs) are located at the deepest points of the boundary of the basins. TSs and minima correspond to stationary points of the PES. Two adjacent minima of the PES can be connected through a TS via a continuous curve in the N-dimensional coordinate space, describing the coordinates of the nuclei. The curve characterizes a RP. The concept of the RP has found a widespread use in descriptions of reaction mechanisms, which are based on geometrical rearrangements of the atoms comprising a given chemical system. [6] Mor...

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Section: Search Of Sp's Of Higher Index By Gad Trajectoriesmentioning

confidence: 99%

Embedding of the saddle point of index two on the PES of the ring opening of cyclobutene

Quapp

Bofill

2015

Int. J. Quantum Chem.

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“…We note that there exists a long list of theoretical developments, 4-7,9-13,19-30 as well as of applications of NTs in Chemistry. [31][32][33][34][35][36][37][38] We can, on the other hand, start with the simplest definition of an NT that the gradient lies in a fixed 1-dimensional subspace 18 or that the gradient of the PES along the curve always points into a given direction:…”

Section: Newton: Trajectories and Homotopymentioning

confidence: 99%

Comment on “Exploring the potential energy landscape of the Thomson problem via Newton homotopies” [J. Chem. Phys. 142, 194113 (2015)]

Bofill

2015

The Journal of Chemical Physics

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“…For complex systems, the potential energy surface becomes more complicated, and transitions from a potential basin to another involve not only index 1 saddles but also higher-index saddles [56][57][58][59][60][61][62][63][64]. Recently, the role of index 2 saddles revealed several dynamical aspects.…”

Section: Introductionmentioning

confidence: 99%

“…Chemical reactions associated with index 2 saddles were also reported in several molecular systems [58][59][60][61][62][63][64] by using several searching algorithms (section 6.3, p. 298, of Ref. [65] and references therein).…”

Section: Introductionmentioning

confidence: 99%

“…Note, however, that it is not necessary for the highest energy point on the minimum energy path between two potential minima to be an index 1 saddle [67]. Moreover, one can still find many studies such as aminoborane [58], PF 3 [58], NH 5 [59], NF 2 H 3 [60], water dimer [61,62], H 5 + [63], and H 2 CO [64] that identify a variety of index 2 saddles in molecular isomerization reactions.…”

Section: Introductionmentioning

confidence: 99%

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Reactivity boundaries for chemical reactions associated with higher-index and multiple saddles

Nagahata

Teramoto

et al. 2013

Phys. Rev. E

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Reactivity boundaries that divide the origin and destination of trajectories are of crucial importance to reveal the mechanism of reactions, which was recently found to exist robustly even at high energies for index 1 saddles [Phys. Rev. Lett. 105, 048304 (2010)]. Here we revisit the concept of the reactivity boundary and propose a more general definition that can involve a single reaction associated with a bottleneck composed of higher-index saddles and/or several saddle points with different indices, where the normal form theory, based on expansion around a single stationary point, does not work. We numerically demonstrate the reactivity boundary by using a reduced model system of the H 5 + cation where the proton exchange reaction takes place through a bottleneck composed of two index 2 saddle points and two index 1 saddle points. The cross section of the reactivity boundary in the reactant region of the phase space reveals which initial conditions are effective in making the reaction happen and thus sheds light on the reaction mechanism.

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Hydrogen bond in FH…FM (M = Li, Na, K) dimers: Nonempirical calculations

Cited by 11 publications

References 11 publications

Embedding of the saddle point of index two on the PES of the ring opening of cyclobutene

Embedding of the saddle point of index two on the PES of the ring opening of cyclobutene

Comment on “Exploring the potential energy landscape of the Thomson problem via Newton homotopies” [J. Chem. Phys. 142, 194113 (2015)]

Reactivity boundaries for chemical reactions associated with higher-index and multiple saddles

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