scholarly journals Flexible boundary layer using exchange for embedding theories. II. QM/MM dynamics of the hydrated electron

Author(s):  
Zhuofan Shen ◽  
Shaoting Peng ◽  
William Glover

The FlexiBLE embedding method introduced in the preceding companion paper [Z. Shen and W. J. Glover, J. Chem. Phys. X, X (2021)] is applied to explore the structure and dynamics of the aqueous solvated electron at an all-electron density functional theory QM/MM level. Compared to a one-electron mixed quantum/classical description, we find the dynamics of the many-electron model of the hydrated electron exhibits enhanced coupling to water OH stretch modes. Natural Bond Orbital analysis reveals this coupling is due to significant population of water OH σ* orbitals, reaching 20%. Based on this, we develop a minimal frontier orbital picture of the hydrated electron involving a cavity orbital and important coupling to 4-5 coordinating OH σ* orbitals. Implications for the interpretation of the spectroscopy of this interesting species are discussed.

2021 ◽  
Author(s):  
Zhuofan Shen ◽  
Shaoting Peng ◽  
William Glover

The FlexiBLE embedding method introduced in the preceding companion paper [Z. Shen and W. J. Glover, J. Chem. Phys. X, X (2021)] is applied to explore the structure and dynamics of the aqueous solvated electron at an all-electron density functional theory QM/MM level. Compared to a one-electron mixed quantum/classical description, we find the dynamics of the many-electron model of the hydrated electron exhibits enhanced coupling to water OH stretch modes. Natural Bond Orbital analysis reveals this coupling is due to significant population of water OH σ* orbitals, reaching 20%. Based on this, we develop a minimal frontier orbital picture of the hydrated electron involving a cavity orbital and important coupling to 4-5 coordinating OH σ* orbitals. Implications for the interpretation of the spectroscopy of this interesting species are discussed.


2021 ◽  
Author(s):  
Zhuofan Shen ◽  
Shaoting Peng ◽  
William Glover

The FlexiBLE embedding method introduced in the preceding companion paper [Z. Shen and W. J. Glover, J. Chem. Phys. X, X (2021)] is applied to explore the structure and dynamics of the aqueous solvated electron at an all-electron density functional theory QM/MM level. Compared to a one-electron mixed quantum/classical description, we find the dynamics of the many-electron model of the hydrated electron exhibits enhanced coupling to water OH stretch modes. Natural Bond Orbital analysis reveals this coupling is due to significant population of water OH σ* orbitals, reaching 20%. Based on this, we develop a minimal frontier orbital picture of the hydrated electron involving a cavity orbital and important coupling to 4-5 coordinating OH σ* orbitals. Implications for the interpretation of the spectroscopy of this interesting species are discussed.


Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4431
Author(s):  
Jiří Czernek ◽  
Jiří Brus

A tetramer model was investigated of a remarkably stable iodine-containing supramolecular capsule that was most recently characterized by other authors, who described emergent features of the capsule’s formation. In an attempt to address the surprising fact that no strong pair-wise interactions between any of the respective components were experimentally detected in condensed phases, the DFT (density-functional theory) computational model was used to decompose the total stabilization energy as a sum of two-, three- and four-body contributions. This model considers complexes formed between either iodine or bromine and the crucial D4h-symmetric form of octaaryl macrocyclic compound cyclo[8](1,3-(4,6-dimethyl)benzene that is surrounded by arenes of a suitable size, namely, either corannulene or coronene. A significant enthalpic gain associated with the formation of investigated tetramers was revealed. Furthermore, it is shown that the total stabilization of these complexes is dominated by binary interactions. Based on these findings, comments are made regarding the experimentally observed behavior of related multicomponent mixtures.


2011 ◽  
Vol 67 (6) ◽  
pp. 535-551 ◽  
Author(s):  
David A. Bardwell ◽  
Claire S. Adjiman ◽  
Yelena A. Arnautova ◽  
Ekaterina Bartashevich ◽  
Stephan X. M. Boerrigter ◽  
...  

Following on from the success of the previous crystal structure prediction blind tests (CSP1999, CSP2001, CSP2004 and CSP2007), a fifth such collaborative project (CSP2010) was organized at the Cambridge Crystallographic Data Centre. A range of methodologies was used by the participating groups in order to evaluate the ability of the current computational methods to predict the crystal structures of the six organic molecules chosen as targets for this blind test. The first four targets, two rigid molecules, one semi-flexible molecule and a 1:1 salt, matched the criteria for the targets from CSP2007, while the last two targets belonged to two new challenging categories – a larger, much more flexible molecule and a hydrate with more than one polymorph. Each group submitted three predictions for each target it attempted. There was at least one successful prediction for each target, and two groups were able to successfully predict the structure of the large flexible molecule as their first place submission. The results show that while not as many groups successfully predicted the structures of the three smallest molecules as in CSP2007, there is now evidence that methodologies such as dispersion-corrected density functional theory (DFT-D) are able to reliably do so. The results also highlight the many challenges posed by more complex systems and show that there are still issues to be overcome.


Author(s):  
Nadezda A. Borshch ◽  
Sergey I. Kurganskii

Представлены результаты моделирования пространственной структуры и электронных свойств кластеров MeGe16 - и MeGe20 - (Me = Sc, Y, Lu). Рассматривается возможность синтеза  пуллереноподобных кластеров и кластеров с другими типами замкнутых структур. Проведены сравнительные расчеты в рамках теории функционала плотности с использованием базиса SDD и трех различных потенциалов – B3LYP, B3PW91 и PBEPBE. Анализируется влияние выбора потенциала на результаты моделирования пространственной структуры кластеров и их электронного спектра. Оценка адекватности теоретических методов проводится путем сравнения рассчитанных электронных спектров с экспериментальными результатами по фотоэлектронной спектроскопии кластеров.     REFERENCES Kroto H. W., Heath J. R., O’Brien S. C., Curl R. F., Smalley R. E. C60: Buckminsterfullerene. Nature, 1985, v. 318, pp. 162-163. https://doi.org/10.1038/318162a0 Hiura H., Miyazaki, Kanayama T. Formation of Metal-Encapsulating Si Cage Clusters. Phys. Rev. Lett., 2001, v. 86, p. 1733. https://doi.org/10.1103/PhysRev-Lett.86.1733 Wang J., Han J. Geometries, stabilities, and electronic properties of different-sized ZrSin (n=1–16) clusters: A density-functional investigation. Chem. Phys., 2005, v. 123(6), pp. 064306–064321. https://doi.org/10.1063/1.1998887 Guo L.-J., Liu X., Zhao G.-F. Computational investigation of TiSin (n=2–15) clusters by the densityfunctional theory. Chem. Phys., 2007, v. 126(23), pp. 234704–234710.  https://doi.org/10.1063/1.2743412 Li J., Wang G., Yao C., Mu Y., Wan J., Han M. Structures and magnetic properties of SinMn (n=1–15) clusters. Chem. Phys., 2009, v. 130(16), pp. 164514–164522.  https://doi.org/10.1063/1.3123805 Borshch N. A., Berestnev K. S., Pereslavtseva N. S., Kurganskii S. I. Geometric structure and electron spectrum of YSi n− clusters (n = 6–17) Physics of the Solid State, 2014, v. 56(6), pp. 1276–1281. https://doi.org/10.1134/S1063783414060080 Borshch N., Kurganskii S. Geometric structure, electron-energy spectrum, and growth of anionic scandium-silicon clusters ScSin- (n = 6–20). Appl. Phys., 2014, v. 116(12), pp. 124302-1 – 124302-8. https://doi.org/10.1063/1.4896528 Borshch N. A., Pereslavtseva N. S., Kurganskii S. I. Spatial structure and electronic spectrum of TiSi n - Clusters (n = 6–18). Russian Journal of Physical Chemistry A, v. 88(10), pp. 1712–1718. https://doi.org/10.1134/S0036024414100070 Borshch N. A., Pereslavtseva N. S., Kurganskii S. I. Spatial and electronic structures of the germanium-tantalum clusters TaGe n − (n = 8–17). Physics of the Solid State, 2014, vol. 56(11), pp. 2336–2342. https://doi.org/10.1134/S1063783414110055 Huang X., Yang J. Probing structure, thermochemistry, electron affi nity, and magnetic moment of thulium-doped silicon clusters TmSi n (n = 3–10) and their anions with density functional theory. Mol. Model., 2018, v. 24(1), p. 29. https://doi.org/10.1007/s00894-017-3566-7 Zhang, Y., Yang, J., Cheng, L. J. Probing Structure, Thermochemistry, Electron Affi nity and Magnetic Moment of Erbium-Doped Silicon Clusters ErSin (n = 3–10) and Their Anions with Density Functional Theory. Sci., 2018, v. 29(2), pp. 301–311. https://doi.org/10.1007/s10876-018-1336-z Ye T., Luo C., Xu B., Zhang S., Song H., Li G. Probing the geometries and electronic properties of charged Zr2Si n q (n = 1–12, q = ±1) clusters. Chem., 2018, v. 29(1), pp. 139–146.  https://doi.org/10.1007/s11224-17-1011-2 Nguyen M.T., Tran Q. T., Tran V.T. A CASSCF/ CASPT2 investigation on electron detachments from ScSi n − (n = 4–6) clusters. Mol. Model., 2017, v. 23(10), p. 282. https://doi.org/10.1007/s00894-017-3461-2 Liu Y., Jucai Yang J., Cheng L. Structural Stability and Evolution of Scandium-Doped Silicon Clusters: Evolution of Linked to Encapsulated Structures and Its Infl uence on the Prediction of Electron Affi nities for ScSin (n = 4–16) Clusters. Chem., 2018, v. 57(20), pp 12934–12940. https://doi.org/10.1021/acs.inorgchem.8b02159


2007 ◽  
Vol 06 (02) ◽  
pp. 363-376 ◽  
Author(s):  
ZHIWEI LI ◽  
CUNYUAN ZHAO ◽  
LIUPING CHEN

The equilibrium geometries, energies, harmonic vibrational frequencies, stability, and aromaticities for the [Formula: see text], E 4 Fe , and [ Fe (η4 - E 4)2]2- ( E = N, P, As, Sb, and Bi ) species are studied using density functional theory (DFT). The ground states of the E 4 Fe and [ Fe (η4 - E 4)2]2- systems are predicted to be Cs and D4d structures, respectively. Orbital analysis indicates that the orbital interactions between the π orbitals of the ligands and the atomic orbitals of the d 6 iron center are the main bonding scheme for these [ Fe (η4 - E 4)2]2- (D4d) complexes. The stability of the [ Fe (η4 - E 4)2]2- complexes exhibits the order P > As > Sb > Bi > N for E. On the basis of comparison with the known ferrocene, the NICS analysis confirms that the [ Fe (η4 - E 4)2]2- (D4d) as well as ferrocene are aromatic. The dissected NICS reveals that the aromaticities of the [ Fe (η4 - E 4)2]2- (D4d) are primarily attributed to the effects of their E–E π bonds and Fe lone pairs.


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