Path-integral molecular dynamics simulations of hydrated hydrogen chloride cluster HCl(H2O)4 on a semiempirical potential energy surface

Takayanagi, Toshiyuki; Takahashi, Kazutoshi; Kakizaki, Akira; Shiga, Motoyuki; Tachikawa, Masanori

doi:10.1016/j.chemphys.2009.01.014

Cited by 18 publications

(25 citation statements)

References 52 publications

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“…Some MM force fields have been employed in conformation searches 93,120 and re-parameterized PM3 was also used for cluster structure samplings. 121,122 Extensive searches for MINs and TSs in medium sized systems including 10 to 20 atoms using a semi-empirical method, the self-consistent charge density functional theory based tight binding (SCC-DFTB) method, 112 are in progress. More extensive tests of l-ADDF in such medium sized systems are also in progress.…”

Section: Other Applications Of Grrm/addfmentioning

confidence: 99%

Systematic exploration of the mechanism of chemical reactions: the global reaction route mapping (GRRM) strategy using the ADDF and AFIR methods

Maeda

Ohno

Morokuma

2013

Phys. Chem. Chem. Phys.

541

543

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Global reaction route mapping (GRRM), a fully-automated search for all important reaction pathways relevant to a given purpose, on the basis of quantum chemical calculations enables systematic elucidation of complex chemical reaction mechanisms. However, GRRM had previously been limited to very simple systems. This is mainly because such calculations are highly demanding even in small systems when a brute-force sampling is considered. Hence, we have developed two independent but complementary methods: anharmonic downward distortion following (ADDF) and artificial force induced reaction (AFIR) methods. ADDF can follow reaction pathways starting from local minima on the potential energy surface (PES) toward transition structures (TSs) and dissociation channels. AFIR can find pathways starting from two or more reactants toward TSs for their associative reactions. In other words, ADDF searches for A → X type isomerization and A → X + Y type dissociation pathways, whereas AFIR finds A + B → X (+ Y) type associative pathways. Both follow special paths called the ADDF path and the AFIR path, and these tend to pass through near TSs of corresponding reaction pathways, giving approximate TSs. Such approximate TSs can easily be re-optimized to corresponding true TSs by standard geometry optimizations. On the basis of these two methods, we have proposed practical strategies of GRRM. The GRRM strategies have been applied to a variety of chemical systems ranging from thermal- and photochemical-reactions in small systems to organometallic- and enzyme-catalysis, on the basis of quantum chemical calculations. In this perspective, we present an overview of the GRRM strategies and some results of applications. Their practical usage for systematic prediction is also discussed.

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Section: Other Applications Of Grrm/addfmentioning

confidence: 99%

Systematic exploration of the mechanism of chemical reactions: the global reaction route mapping (GRRM) strategy using the ADDF and AFIR methods

Maeda

Ohno

Morokuma

2013

Phys. Chem. Chem. Phys.

541

543

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“…Water clusters are the archetypal example of complicated energy landscapes populated by multitudes of structurally unrelated local minima, which in several cases are not discernible from the corresponding global minimum using either experimental or theoretical methods. The situation is further complicated by low interconversion barriers and by consideration of temperature, entropy, and internal degrees of freedom, which usually shuffle stability orders in favor of more open structures as the temperature increases, eventually leading to ideal gas behavior at sufficiently high temperatures . Computations on interactions of water with HCl, dissociated or not, have been performed through intuitive construction of initial guesses for cluster structures (see Leopold's review for a more comprehensive list of theoretical calculations on the subject), with the aim of identifying the structural preferences for all possible combinations of interacting species that could be found in HCl/water mixtures.…”

Section: Introductionmentioning

confidence: 99%

How Many Water Molecules Does it Take to Dissociate HCl?

Vargas-Caamal

Cabellos

Ortíz‐Chi³

et al. 2016

Chemistry A European J

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The potential energy surfaces of the HCl(H2O)n (n is the number of water molecules) clusters are systematically explored using density functional theory and high-level ab initio computations. On the basis of electronic energies, the number of water molecules needed for HCl dissociation is four as reported by some experimental groups. However, this number is five owing to the inclusion of entropic factors. Wiberg bond indices are calculated and analyzed, and the results provide a quadratic correlation and classification of clusters according to the nondissociated, partially dissociated, and fully dissociated character of the H-Cl bond. Our computations show that if temperature is not controlled during the experiment, the values obtained for the dipole moment (or for any measurable property) are susceptible to change, providing a different picture of the number of water molecules needed for HCl dissociation in a nanoscopic droplet.

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“…We show that in a screening test with GRRM 14 the present approach significantly reduces the computational time compared to GAMESS. Although semiempirical methods implemented in GAUSSIAN have been used previously with GRRM [20], it is much more efficient to use MOPAC directly, as will be evident from the present paper. Thus, as long as the semiempirical method chosen is qualitatively correct, the method proposed herein is highly desirable for large molecular systems.…”

Section: Introductionmentioning

confidence: 96%

A screened automated structural search with semiempirical methods

Ota

Ruiz-Barragan

Machida

et al. 2016

Chemical Physics Letters

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We developed an interface program between a program suite for an automated search of chemical reaction pathways, GRRM, and a program package of semiempirical methods, MOPAC. A two-step structural search is proposed as an application of this interface program. A screening test is first performed by semiempirical calculations. Subsequently, a reoptimization procedure is done by ab initio or density functional calculations. We apply this approach to ion adsorption on cellulose. The computational efficiency is also shown for a GRRM search. The interface program is suitable for the structural search of large molecular systems for which semiempirical methods are applicable.

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Path-integral molecular dynamics simulations of hydrated hydrogen chloride cluster HCl(H2O)4 on a semiempirical potential energy surface

Cited by 18 publications

References 52 publications

Systematic exploration of the mechanism of chemical reactions: the global reaction route mapping (GRRM) strategy using the ADDF and AFIR methods

Systematic exploration of the mechanism of chemical reactions: the global reaction route mapping (GRRM) strategy using the ADDF and AFIR methods

How Many Water Molecules Does it Take to Dissociate HCl?

A screened automated structural search with semiempirical methods

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