Article
Chemistry, Physical
Asylbek A. A. Zhanserkeev, Emily Y. L. Yang, Ryan P. P. Steele
Summary: Ab initio computersimulations of anharmonicvibrationalspectra provide detailed understanding of molecular and complex vibrational behavior. The generation of mode-coupling potentials is the computational bottleneck in such simulations, which can be addressed using a combination of local-mode representation and multilevel methods. By predicting pairwise couplings at a low level of quantum chemistry and recycling excluded pairs at a low level of theory, accurate vibrational self-consistent field calculations can be achieved. Distance-based truncation of low-level predictions further improves computational efficiency without significant loss of accuracy. This combined approach shows promising results in test cases and has potential for accelerating larger systems and higher-order couplings.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Chemistry, Physical
Chih-Kai Lin, Jer-Lai Kuo
Summary: In this work, the vibrational spectra of ammonium, methylammonium, and dimethylammonium ions solvated by either water molecules or bisulfate anions were analyzed using anharmonic vibrational algorithms. The observed spectral features were attributed to strong Fermi resonance and combination tones. Similarities in band positions and spectral patterns between different solvation environments indicate a common vibrational coupling scheme.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Kasper Tolborg, Aron Walsh
Summary: The researchers investigated the tetragonal-to-cubic phase transition of ZrO2 at high temperatures using anharmonic lattice dynamics and molecular dynamics simulations. They found that the stability of cubic zirconia cannot be solely explained by anharmonic stabilization, but may also involve spontaneous defect formation and entropic stabilization, which is responsible for its superionic conductivity at elevated temperatures.
CRYSTAL GROWTH & DESIGN
(2023)
Article
Chemistry, Physical
Jing-Min Liu, Tomoki Nishigori, Toshihiko Maeyama, Qian-Rui Huang, Marusu Katada, Jer-Lai Kuo, Asuka Fujii
Summary: This study uses infrared photodissociation spectroscopy to investigate the ability of water to form hemibonds, providing firm evidence of water's hemibond formation capability.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Thermodynamics
Stephen J. Klippenstein, Peter Glarborg
Summary: Recent modeling studies of NH3 oxidation show significant discrepancies, with high-level theoretical kinetics predictions for the NH2 + HO2 reaction deviating significantly from values used in most previous modeling studies.
COMBUSTION AND FLAME
(2022)
Article
Chemistry, Medicinal
Gabriel Rath, Wassja A. Kopp, Kai Leonhard
Summary: This study introduces a new semiclassical method called configuration integral Monte Carlo integration (CIMCI) for handling fully coupled anharmonicity in gas-phase thermodynamics. It promises to be black boxable, applicable to all kinds of anharmonicity, and to scale better at higher dimensionality compared to other methods. The method uses simultaneous Monte Carlo integration of multiple functions and shows better agreement with reference data for anharmonic entropy corrections in small systems like H2O and H2O2.
JOURNAL OF CHEMICAL INFORMATION AND MODELING
(2021)
Article
Chemistry, Organic
Shih-Yun Chen, Rong Chang, Zhong-Xin Lin, Chien-Wen Lin, Li-Ching Shen, Andrew C. -H. Sue, Mei-Chun Tseng, Jean-Ho Chu
Summary: In this study, a facile synthetic method to produce N-(CH2-aryl/alkyl)-substituted N-(pyridin-2-yl)benzamides via palladium-mediated C(sp(3))-H bond activation was presented. The structures of the dinuclear palladacycle intermediates, which were formed by reacting the N-methyl-N-(pyridin-2-yl)benzamide precursor with palladium(II) acetate, were elucidated by various analyses. The subsequent C(sp(3))-H bond functionalizations on the N-methyl group of the starting substrate showed easy productions of the desired N-(CH2-aryl/alkyl)-substituted N-(pyridin-2-yl)benzamides with good functional group tolerance. A plausible mechanism was proposed based on computational calculations and kinetic isotope effect experiments. Furthermore, the successful transformation of the prepared N-(CH2-aryl)-N-(pyridin-2-yl)benzamides to N-(CH2-aryl)-2-aminopyridine was demonstrated.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Jonas Amsler, Philipp N. Plessow, Felix Studt, Tomas Bucko
Summary: In this paper, a new method for calculating anharmonic contributions to free energy barriers, called constrained thermodynamic lambda-path integration (lambda-TI), is introduced as an alternative to the established Blue Moon ensemble method (xi-TI). The lambda-TI method is benchmarked against the xi-TI method for several reactions and shows good agreement in all cases. An advantage of lambda-TI is its ability to use any reference state to compute anharmonic contributions, which is particularly useful for catalysis. Additionally, the combination of the Bennett acceptance ratio method with lambda-TI is demonstrated to improve computational efficiency.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Chemistry, Physical
Sruthy K. Chandy, Krishnan Raghavachari
Summary: We have developed an efficient protocol for predicting NMR chemical shifts of large nucleic acids using a fragment-based quantum chemical approach. The performance of the approach was assessed on a test set of three nucleic acids and was found to be accurate and cost-effective. The proposed protocol can aid in the structural assignments of complex biomolecules.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Physics, Applied
Jinhao Su, Zhaofu Zhang, Xuhao Wan, Wei Yu, Anyang Wang, Hongxia Zhong, John Robertson, Yuzheng Guo
Summary: By using the density functional theory and ab initio molecular dynamics simulations, this study investigates the structural, electronic, and optical properties of Sb-rich amorphous Ge3Sb6Te5. The results demonstrate that excess Sb concentration enhances the structural stability and improves the electrical and optical property contrast between crystalline and amorphous phases. These findings provide a theoretical basis for utilizing Sb-rich Ge3Sb6Te5 in prolonged service.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Multidisciplinary
Yang Huang, Michael Widom
Summary: This study investigates the vibrational entropy of a solid at finite temperature from the perspective of information theory. By using ab initio molecular dynamics simulations, the N-body distribution of atomic displacements at finite temperature is obtained, and the information-theoretic entropy is calculated. The results show good agreement with experimental values and the method is applicable to complex solids and cases where the quasiharmonic approximation fails.
Article
Astronomy & Astrophysics
M. Companys Franzke, A. Tichai, K. Hebeler, A. Schwenk
Summary: Eigenvector continuation (EC) is a widely used method in nuclear structure and reactions for variational resummation of many-body systems. This work focuses on the emergence of excited states from the EC approach and investigates its performance compared to full diagonalization using the quartic anharmonic oscillator as a test case.
Article
Chemistry, Multidisciplinary
Flor Maria Briceno-Vargas, Mariana Quesadas-Rojas, Gumersindo Miron-Lopez, David Caceres-Castillo, Ruben M. Carballo, Gonzalo J. Mena-Rejon, Ramiro F. Quijano-Quinones
Summary: This study investigates the n -> pi* interactions in amides and thioamides systems models through the analysis of electron density topology. The results suggest that dispersion forces play a significant role in the strength of these interactions.
Article
Chemistry, Physical
Raymond G. Schireman, Jefferson Maul, Alessandro Erba, Michael T. Ruggiero
Summary: The anharmonicity of O-H stretching vibrations of water ice was investigated using VSCF and VCI methods, revealing a complex change in spectral positions due to coupled anharmonic treatment. By coupling O-H stretches with all other possible modes, specific types of motion affecting O-H stretching states were identified.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2022)
Article
Thermodynamics
Qiren Zhu, Jie-Yao Lyu, Ruining He, Xin Bai, Yang Li, Wenming Yang
Summary: In this study, high-level ab initio quantum chemical calculations were performed on PODE3 to investigate its reaction pathways and rate constants. The results provide a solid foundation for developing detailed mechanisms for PODE4-5.
COMBUSTION AND FLAME
(2023)
Article
Chemistry, Physical
Sergey Yu. Ketkov, Sheng-Yuan Tzeng, Elena A. Rychagova, Anton N. Lukoyanov, Wen-Bih Tzeng
Summary: Metallocenes, including methylcobaltocene, play important roles in various fields of chemistry. The ionization energy and vibrational structure of (Cp ')(Cp)Co can be influenced by introducing methyl substituents. The mass-analyzed threshold ionization spectrum and DFT calculations provide accurate information about the properties and transformations of (Cp ')(Cp)Co.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Review
Chemistry, Physical
Qifeng Mu, Jian Hu
Summary: Polymer mechanochemistry has experienced a renaissance due to the rapid development of mechanophores and principles governing mechanochemical transduction or material strengthening. It has not only provided fundamental guidelines for converting mechanical energy into chemical output, but also found applications in engineering and smart devices.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Da Hye Yang, Francesco Ricci, Fredrik L. Nordstrom, Na Li
Summary: Through systematic evaluation of the oiling-out behavior of procaine, we identified both stable and metastable liquid-liquid phase separation, and established phase diagrams to assist in rational selection of crystallization strategies.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Vikki Anand Varma, Simmie Jaglan, Mohd Yasir Khan, Sujin B. Babu
Summary: Designing engineering structures like nanocages, shells, and containers through self-assembly of colloids is a challenging problem. This work proposes a simple model for the subunit, which leads to the formation of monodispersed spherical cages or containers. The model with only one control parameter can be used to design cages with the desired radius.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Hainan Jiang, Yaolong He, Xiaolin Li, Zhiyao Jin, Huijie Yu, Dawei Li
Summary: The cycling lifespan and coulombic efficiency of lithium-ion batteries are crucial for high C-rate applications. The Li-ion concentration plays a crucial role in determining the mechanical integrity and structural stability of electrodes. This study focuses on graphite as the working electrode and establishes an experimental system to investigate the mechanical properties of composite graphite electrode at different C-rates. Considering the effect of Li-ion concentration in stress analysis is found to be significant.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Zhiye Wang, Yunchuan Li, Mingjun Sun
Summary: This study investigates the influence of intramolecular pi-pi interactions on the electronic transport capabilities of molecules. By designing and analyzing three pi-conjugated molecules, the researchers observe that different pi-conjugated structures have varying effects on electron transport. The findings provide a theoretical foundation for designing single-molecule electronic devices with multiple electron channels based on intramolecular pi-pi interactions.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Yuandong Xu, Haoyang Feng, Chaoyang Dong, Yuqing Yang, Meng Zhou, Yajun Wei, Hui Guo, Yaqing Wei, Jishan Su, Yingying Ben, Xia Zhang
Summary: Hollow MoS2 cubes and spheres were successfully synthesized using a one-step hydrothermal method with the hard template method. The hollow MoS2 cubes exhibited higher specific capacitance and energy density compared to the hollow MoS2 spheres. The symmetrical supercapacitors assembled with these hollow structures showed good performance and high capacity retention after multiple cycles. These findings suggest that controlling the pore structure and surface characteristics of MoS2 is crucial for enhancing its electrochemical properties.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Ainhoa Oliden-Sanchez, Rebeca Sola-Llano, Joaquin Perez-Pariente, Luis Gomez-Hortiguela, Virginia Martinez-Martinez
Summary: The combination of photoactive molecules and inorganic structures is important for the development of advanced materials in optics. In this study, bulky dyes were successfully encapsulated in a zeolitic framework, resulting in emission throughout the visible spectrum.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Miaomiao Zhang, Cunyuan Pei, Qiqi Xiang, Lintao Liu, Zhongxu Dai, Huijuan Ma, Shibing Ni
Summary: The design of a solid electrolyte interphase (SEI) plays a crucial role in improving the electrochemical performance of anode materials. In this study, lithium difluoro(oxalate)borate (LiDFOB) is used as an electrolyte additive to form a protective SEI film on Li3VO4 (LVO) anodes. The addition of LiDFOB results in a dense, uniform, stable, and LiF-richer SEI, which enhances the Li-ion storage kinetics. The generated SEI also prevents further decomposition of the electrolyte and maintains the morphology of LVO anodes during charge/discharge processes. This work demonstrates the effectiveness of LiDFOB as a multi-functional additive for LiPF6 electrolytes and provides insights into SEI construction for high-performance LVO anodes.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
B. V. Andryushechkin, T. V. Pavlova, V. M. Shevlyuga
Summary: The atomic structure of the Ag(111)-p(4 x 4)-O phase was reexamined and two phases with the same periodicity were discovered. It was demonstrated that the accepted Ag6 model is incompatible with high-resolution oxygen-sensitive STM images.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
S. L. Romo-Avila, D. Marquez-Ruiz, R. A. Guirado-Lopez
Summary: In this study, we used density functional theory (DFT) calculations to investigate the interaction between model graphene oxide (GO) nanostructures and chlorine monoxide ClO. We aimed to understand the role of this highly oxidizing species in breaking C-C bonds and forming significant holes on GO sheets. Our results showed that C-C bonds in a single graphene oxide sheet can be broken through a simple mechanism involving the dissociation of two chemically attached ClO molecules. The formation of carbonyl groups and holes on the GO surface was also observed. This study provides important insights into the degradation of carbon nanotubes and the stability of GO during the myeloperoxidase (MPO) catalytic cycle.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Alberto Garcia-Fernandez, Birgit Kammlander, Stefania Riva, Hakan Rensmo, Ute B. Cappel
Summary: In this study, the X-ray stability of five different lead halide perovskite compositions (MAPbI3, MAPbCl3, MAPbBr3, FAPbBr3, CsPbBr3) was investigated using photoelectron spectroscopy. Different degradation mechanisms and resistance to X-ray were observed depending on the crystal composition. Overall, perovskite compositions based on the MA+ cation were found to be less stable than those based on FA+ or Cs+. Metallic lead formation was most easily observed in the chloride perovskite, followed by bromide, and very little in MAPbI3. Multiple degradation processes were identified for the bromide compositions, including ion migration, formation of volatile and solid products, as well as metallic lead. CsBr was formed as a solid degradation product on the surface of CsPbBr3.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Timofei Rostilov, Vadim Ziborov, Alexander Dolgoborodov, Mikhail Kuskov
Summary: The shock-loading behavior of nanomaterials is investigated in this study. It is found that shock compaction waves exhibit a distinct two-step structure, with the formation of faster precursor waves that travel ahead of the main compaction waves. The complexity of the shock Hugoniot curve of the tested nanomaterial is described, and the effect of initial porosity on the compressed states is demonstrated.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Sergey S. Nikitin, Alexander D. Koryakov, Elizaveta A. Antipinskaya, Alexey A. Markov, Mikhail V. Patrakeev
Summary: The stability of La1/3Sr2/3Fe1-xMnxO3-delta, a perovskite-type oxide, under reducing conditions is dependent on the manganese content. Increasing the manganese content leads to a decrease in stability. The behavior of iron and manganese in the oxide shows distinct differences, which can be attributed to the difference in the enthalpy of oxidation reactions. Additionally, the change in the La/Sr ratio affects the concentration of iron and manganese ions.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Mosayeb Naseri, Shirin Amirian, Mehrdad Faraji, Mohammad Abdur Rashid, Maicon Pierre Lourenco, Venkataraman Thangadurai, D. R. Salahub
Summary: Inspired by the successful transfer of freestanding ultrathin films of SrTiO3 and BiFeO3, this study assessed the structural stability and investigated the electronic, optical, and thermoelectric properties of a group of two-dimensional perovskite-type materials called perovskenes. The findings revealed that these materials are wide bandgap semiconductors with potential application in UV shielding. Moreover, they exhibit better electrical and thermal conductivity at high temperatures, enabling efficient power generation in thermoelectric devices.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)