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  Subjects -> CHEMISTRY (Total: 922 journals)
    - ANALYTICAL CHEMISTRY (56 journals)
    - CHEMISTRY (656 journals)
    - CRYSTALLOGRAPHY (21 journals)
    - ELECTROCHEMISTRY (28 journals)
    - INORGANIC CHEMISTRY (43 journals)
    - ORGANIC CHEMISTRY (47 journals)
    - PHYSICAL CHEMISTRY (71 journals)

CHEMISTRY (656 journals)                  1 2 3 4 | Last

Showing 1 - 200 of 735 Journals sorted alphabetically
2D Materials     Hybrid Journal   (Followers: 14)
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 31)
ACS Catalysis     Hybrid Journal   (Followers: 53)
ACS Chemical Neuroscience     Hybrid Journal   (Followers: 23)
ACS Combinatorial Science     Hybrid Journal   (Followers: 23)
ACS Macro Letters     Hybrid Journal   (Followers: 28)
ACS Medicinal Chemistry Letters     Hybrid Journal   (Followers: 45)
ACS Nano     Hybrid Journal   (Followers: 331)
ACS Photonics     Hybrid Journal   (Followers: 15)
ACS Symposium Series     Full-text available via subscription   (Followers: 1)
ACS Synthetic Biology     Hybrid Journal   (Followers: 25)
Acta Chemica Iasi     Open Access   (Followers: 6)
Acta Chimica Slovaca     Open Access   (Followers: 2)
Acta Chimica Slovenica     Open Access   (Followers: 1)
Acta Chromatographica     Full-text available via subscription   (Followers: 8)
Acta Facultatis Medicae Naissensis     Open Access  
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 7)
Acta Scientifica Naturalis     Open Access   (Followers: 2)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 8)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 9)
Adsorption Science & Technology     Open Access   (Followers: 7)
Advanced Functional Materials     Hybrid Journal   (Followers: 62)
Advanced Science Focus     Free   (Followers: 5)
Advances in Chemical Engineering and Science     Open Access   (Followers: 77)
Advances in Chemical Science     Open Access   (Followers: 21)
Advances in Chemistry     Open Access   (Followers: 27)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 20)
Advances in Drug Research     Full-text available via subscription   (Followers: 26)
Advances in Environmental Chemistry     Open Access   (Followers: 7)
Advances in Enzyme Research     Open Access   (Followers: 11)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 9)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 17)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 12)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 28)
Advances in Nanoparticles     Open Access   (Followers: 17)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 17)
Advances in Polymer Science     Hybrid Journal   (Followers: 45)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 19)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 20)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 6)
Advances in Science and Technology     Full-text available via subscription   (Followers: 12)
African Journal of Bacteriology Research     Open Access  
African Journal of Chemical Education     Open Access   (Followers: 4)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 8)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Al-Kimia : Jurnal Penelitian Sains Kimia     Open Access  
Alchemy : Journal of Chemistry     Open Access   (Followers: 3)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 2)
Alotrop     Open Access  
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 69)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 22)
American Journal of Chemistry     Open Access   (Followers: 34)
American Journal of Plant Physiology     Open Access   (Followers: 13)
American Mineralogist     Hybrid Journal   (Followers: 15)
Anadolu University Journal of Science and Technology A : Applied Sciences and Engineering     Open Access  
Analyst     Full-text available via subscription   (Followers: 37)
Angewandte Chemie     Hybrid Journal   (Followers: 189)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 277)
Annales Universitatis Mariae Curie-Sklodowska, sectio AA – Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 4)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 3)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 4)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (Followers: 9)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 12)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 15)
Antiviral Chemistry and Chemotherapy     Open Access   (Followers: 2)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 9)
Applied Spectroscopy     Full-text available via subscription   (Followers: 26)
Applied Surface Science     Hybrid Journal   (Followers: 34)
Arabian Journal of Chemistry     Open Access   (Followers: 6)
ARKIVOC     Open Access   (Followers: 1)
Asian Journal of Biochemistry     Open Access   (Followers: 3)
Asian Journal of Chemistry and Pharmaceutical Sciences     Open Access   (Followers: 2)
Atomization and Sprays     Full-text available via subscription   (Followers: 4)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 7)
Autophagy     Hybrid Journal   (Followers: 4)
Avances en Quimica     Open Access  
Biochemical Pharmacology     Hybrid Journal   (Followers: 11)
Biochemistry     Hybrid Journal   (Followers: 385)
Biochemistry Insights     Open Access   (Followers: 7)
Biochemistry Research International     Open Access   (Followers: 7)
BioChip Journal     Hybrid Journal  
Bioinorganic Chemistry and Applications     Open Access   (Followers: 11)
Bioinspired Materials     Open Access   (Followers: 5)
Biointerface Research in Applied Chemistry     Open Access   (Followers: 2)
Biointerphases     Open Access   (Followers: 1)
Biology, Medicine, & Natural Product Chemistry     Open Access   (Followers: 2)
Biomacromolecules     Hybrid Journal   (Followers: 24)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 10)
Biomedical Chromatography     Hybrid Journal   (Followers: 6)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 3)
BioNanoScience     Partially Free   (Followers: 6)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 144)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 95)
Bioorganic Chemistry     Hybrid Journal   (Followers: 10)
Biopolymers     Hybrid Journal   (Followers: 20)
Biosensors     Open Access   (Followers: 2)
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 1)
Bitácora Digital     Open Access  
Boletin de la Sociedad Chilena de Quimica     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 1)
Bulletin of the Chemical Society of Japan     Full-text available via subscription   (Followers: 25)
Bulletin of the Korean Chemical Society     Hybrid Journal   (Followers: 1)
C - Journal of Carbon Research     Open Access   (Followers: 3)
Cakra Kimia (Indonesian E-Journal of Applied Chemistry)     Open Access  
Canadian Association of Radiologists Journal     Full-text available via subscription   (Followers: 2)
Canadian Journal of Chemistry     Hybrid Journal   (Followers: 12)
Canadian Mineralogist     Full-text available via subscription   (Followers: 7)
Carbohydrate Research     Hybrid Journal   (Followers: 25)
Carbon     Hybrid Journal   (Followers: 71)
Catalysis for Sustainable Energy     Open Access   (Followers: 10)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 10)
Catalysis Science and Technology     Hybrid Journal   (Followers: 10)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysts     Open Access   (Followers: 14)
Cellulose     Hybrid Journal   (Followers: 13)
Cereal Chemistry     Full-text available via subscription   (Followers: 5)
ChemBioEng Reviews     Full-text available via subscription   (Followers: 2)
ChemCatChem     Hybrid Journal   (Followers: 8)
Chemical and Engineering News     Free   (Followers: 23)
Chemical Bulletin of Kazakh National University     Open Access  
Chemical Communications     Full-text available via subscription   (Followers: 75)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 28)
Chemical Physics Letters : X     Open Access  
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 3)
Chemical Research in Toxicology     Hybrid Journal   (Followers: 22)
Chemical Reviews     Hybrid Journal   (Followers: 222)
Chemical Science     Open Access   (Followers: 30)
Chemical Technology     Open Access   (Followers: 36)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 5)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 57)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 21)
ChemInform     Hybrid Journal   (Followers: 8)
Chemistry     Open Access  
Chemistry & Biodiversity     Hybrid Journal   (Followers: 7)
Chemistry & Biology     Full-text available via subscription   (Followers: 34)
Chemistry & Industry     Full-text available via subscription   (Followers: 8)
Chemistry - A European Journal     Hybrid Journal   (Followers: 185)
Chemistry - An Asian Journal     Hybrid Journal   (Followers: 16)
Chemistry and Materials Research     Open Access   (Followers: 21)
Chemistry Central Journal     Open Access   (Followers: 4)
Chemistry Education Research and Practice     Free   (Followers: 5)
Chemistry in Education     Open Access   (Followers: 9)
Chemistry International     Open Access   (Followers: 3)
Chemistry Letters     Full-text available via subscription   (Followers: 46)
Chemistry of Heterocyclic Compounds     Hybrid Journal   (Followers: 4)
Chemistry of Materials     Hybrid Journal   (Followers: 281)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 10)
Chemistry World     Full-text available via subscription   (Followers: 21)
Chemistry-Didactics-Ecology-Metrology     Open Access   (Followers: 1)
ChemistryOpen     Open Access   (Followers: 1)
Chemkon - Chemie Konkret, Forum Fuer Unterricht Und Didaktik     Hybrid Journal  
Chemoecology     Hybrid Journal   (Followers: 3)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 15)
Chemosensors     Open Access  
ChemPhysChem     Hybrid Journal   (Followers: 12)
ChemPlusChem     Hybrid Journal   (Followers: 2)
ChemTexts     Hybrid Journal  
CHIMIA International Journal for Chemistry     Full-text available via subscription   (Followers: 2)
Chinese Journal of Chemistry     Hybrid Journal   (Followers: 6)
Chinese Journal of Polymer Science     Hybrid Journal   (Followers: 11)
Chromatographia     Hybrid Journal   (Followers: 22)
Chromatography     Open Access   (Followers: 3)
Chromatography Research International     Open Access   (Followers: 5)
Clay Minerals     Hybrid Journal   (Followers: 10)
Cogent Chemistry     Open Access   (Followers: 2)
Colloid and Interface Science Communications     Open Access  
Colloid and Polymer Science     Hybrid Journal   (Followers: 11)
Colloids and Interfaces     Open Access  
Colloids and Surfaces B: Biointerfaces     Hybrid Journal   (Followers: 7)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 4)
Combustion Science and Technology     Hybrid Journal   (Followers: 23)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 2)
Communications Chemistry     Open Access   (Followers: 2)
Composite Interfaces     Hybrid Journal   (Followers: 8)
Comprehensive Chemical Kinetics     Full-text available via subscription   (Followers: 1)
Comptes Rendus Chimie     Full-text available via subscription  
Comptes Rendus Physique     Full-text available via subscription   (Followers: 1)
Computational and Theoretical Chemistry     Hybrid Journal   (Followers: 9)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 13)
Computational Chemistry     Open Access   (Followers: 3)
Computers & Chemical Engineering     Hybrid Journal   (Followers: 10)
Coordination Chemistry Reviews     Full-text available via subscription   (Followers: 4)
Copernican Letters     Open Access   (Followers: 1)
Corrosion Series     Full-text available via subscription   (Followers: 7)
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 8)
Croatica Chemica Acta     Open Access  
Crystal Structure Theory and Applications     Open Access   (Followers: 4)
CrystEngComm     Full-text available via subscription   (Followers: 13)
Current Catalysis     Hybrid Journal   (Followers: 2)
Current Chromatography     Hybrid Journal  
Current Green Chemistry     Hybrid Journal   (Followers: 2)
Current Metabolomics     Hybrid Journal   (Followers: 6)
Current Microwave Chemistry     Hybrid Journal  
Current Opinion in Colloid & Interface Science     Hybrid Journal   (Followers: 9)
Current Opinion in Molecular Therapeutics     Full-text available via subscription   (Followers: 14)
Current Research in Chemistry     Open Access   (Followers: 9)
Current Science     Open Access   (Followers: 77)

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Similar Journals
Journal Cover
Computational and Theoretical Chemistry
Journal Prestige (SJR): 0.506
Citation Impact (citeScore): 1
Number of Followers: 9  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 2210-271X
Published by Elsevier Homepage  [3185 journals]
  • How much aromatic are naphthalene and graphene'
    • Abstract: Publication date: Available online 11 June 2019Source: Computational and Theoretical ChemistryAuthor(s): Vaibhav A. Dixit, Yashita Y. Singh Naphthalene, polyacenes and graphene are considered aromatic. Existing models for polyacenes predict a linearly increasing aromatic stabilization energy (ASE) and give little insights into their high reactivity and decreasing stability. Graphene’s aromaticity has been studied only qualitatively suggesting alternate Clar’s sextet and two-electrons per ring, and ASE estimates are missing. In this paper, various Enthalpy of Hydrogenation (ΔHhydro) and isodesmic schemes have been proposed and compared for the estimation of naphthalene ASE. Results show that ΔHhydro schemes are simple to design, are equivalent to isodesmic schemes, and unconjugated unsaturated reference systems predict ASE values in agreement with literature reports. Partially aromatic reference systems underestimate ASE. ΔHhydro schemes require calculations for a smaller number of structures, and offer scope for experimental validation, and involve enthalpy differences. Polyacene (X-axis extensions of benzene) ASE estimates (using ΔHhydro scheme) correlate well with experimental instability data and offer new chemical physical insights. ASEs extrapolated from quadratic and logarithmic regression models have been used to estimate the largest polyacene with limiting ASE values. ASE values for Pyrene (Y-axis extension of benzene) and higher analogues (here called pyrene-vertacenes) are estimated using ΔHhydro schemes. Further truncated graphene models and graphene are approximated as combinations of polyacene and pyrene-vertacene units. First ever ASE and molecular sizes (22-255 nM) estimates predict nanometer size ranges for flat graphene in agreement with recent experiments and offer new physical insights. These ASE and size estimates for graphene will prove useful in the design of novel energy (hydrogen) storage, electronic and material science applications.Graphical abstractGraphical abstract for this article
       
  • A Computational DFT Study of Methane C−H and Ammine N−H Activations by
           Group 9 N-Pyrrolyl Complexes
    • Abstract: Publication date: Available online 7 June 2019Source: Computational and Theoretical ChemistryAuthor(s): Bruce M. Prince A density functional theory with solvation model density analysis of methane C−H and ammine N−H activations with Group 9 N-pyrrolyl phosphine complexes (Co, Rh, Ir) is presented. Analysis of the reaction, [{(pyr)3P}M(NH2)]q+, (where M signify Co, Rh, Ir; pyr = N−pyrrolyl and q = +1 and +3 for d8 and d6 Group 9) showed that Ir system occurs with a lower free energy barrier. The computed complexes all have reasonable C−H activation barriers, ΔG‡ ∼ 18 to 32 kcal/mol, which tracks with the electron density on the metal center of the transition state complexes. Ammine N−H activation barriers are discreetly low, which emphasize the square planar, [{(pyr)3P}M(Py)(NH3)(OCH3)], complexes are uniquely ready to aid the reaction cycle within a single step. Thus, such ligands are worthy of experimental study due to their ability of strong π-backbonding, which may meet the strong metal-to-ligand coordination demands of an acidic environment of methanol production.Graphical abstractGraphical abstract for this article
       
  • Development of fullerene free acceptors molecules for organic solar cells:
           A step way forward toward efficient organic solar cells
    • Abstract: Publication date: Available online 3 June 2019Source: Computational and Theoretical ChemistryAuthor(s): Muhammad Ans, Khurshid Ayub, Shabbir Muhammad, Javed Iqbal Continuous strides are being made to explore non-fullerene acceptors for organic solar cells. Here, optoelectronic properties of four new acceptor-donor-acceptor (A-D-A) type non-fullerene acceptor molecules are evaluated for their potential use in organic solar cells. The designed molecules contain indacenodithiophene (IDT) donor core connected with various acceptor groups through benzothiadiazole (BT) bridge unit. The designed molecules differ from each other in end-capped acceptor groups. The end-capped acceptors are 2-methylene-3-oxo-2,3-dihydroinden-1-ylidene) malononitrile (M1), 2,5,6-difluoro-2-methylene-3-oxo-2,3-dihydroinden-1-ylidene) malononitrile (M2), 2-methylene-2-H-indene-1,3-dione (M3), and 2,5-methylene-6-oxo-5,6-dihydrocyclopenta-c-thiphen-4-ylidene-malononitrile (M4). The optoelectronic properties are evaluated in comparison with the recently reported R which is structurally similar to the designed molecules. The reference compound R contains indacenodithiophene (IDT) donor core unit with 3-ethyl-d-ethylidene-2-thioxothiazolidin-4-one end capped acceptor group. The A-D-A acceptor molecules evaluated here exhibit proper frontier molecular orbital diagram to facilitate the charge mobility. M2, containing 2-(5,6-difluoro-2-methylene-3-oxo-2,3-dihydroinden-1-ylidene) malononitrile end-capped acceptor group, exhibits maximum absorption at 805 nm which is attributed to extended conjugation with the BT unit. Results of transition density matrix (TDM) show clear effect of end caped acceptor group on electro-hole exciton. Small coupling of electron and hole in M4 illustrates easy dissociation of exciton as compared with other molecules. Among all, M4 shows the highest hole transfer rate as revealed from low hole reorganization energy (λh). The open circuit voltage (Voc) of reference R is 1.96 V with donor polymer PTB7-Th while the designed molecule M3 exhibits the Voc of 2.02 V. Hence, the designed fullerene free acceptor molecules are suitable for transparent organic solar cells.Graphical abstractGraphical abstract for this article
       
  • Modeling and spectral simulation of formic acid dimer in Ar matrix using
           ONIOM calculations
    • Abstract: Publication date: Available online 3 June 2019Source: Computational and Theoretical ChemistryAuthor(s): Fumiyuki Ito The supermolecule approach has been used to model molecules embedded in a solid argon matrix. The interaction between the guest and the host atoms in the first solvation shell (FSS) are evaluated using density functional calculations while that beyond the FSS is incorporated using ONIOM calculations to extend the results of our previous study [F. Ito, J. Chem. Phys. 133 (2010) 214502]. The vibrational spectra of a formic acid dimer (FAD) in an Ar matrix was simulated using (FAD)-Arn clusters (n = 94–1095). Structural relaxation in the first solvation shell is crucial to quantitatively reproduce the matrix shifts of fundamental bands, according to calculations at the B971/6-31++G(3df,3pd) level. Moreover, the influence of the outer Ar atoms is negligible.Graphical abstractStructural relaxation of Ar atoms in the first solvation shell.Graphical abstract for this article
       
  • Quantum molecular dynamic approach to modeling the vibrational spectra of
           propynenitrile and its 1:1 complexes with water
    • Abstract: Publication date: Available online 3 June 2019Source: Computational and Theoretical ChemistryAuthor(s): Claude Pouchan We present here a quantum molecular dynamic approach from DFT molecular dynamics (DFT/MD) trajectories around 150K, 300K, 450K and 600K to compute the IR spectra of the propynenitrile (or cyanoacetylene) molecule HC3N, the simplest linear cyanopolyyne detected in interstellar clouds and circumstellar envelopes of stars. The DFT/MD results in fair agreement with the experimental data for the isolated molecule are close to those obtained, for all the valence modes, from an effective second order treatment (VPT2) at the CCSD(T) level of theory. This DFT/MD simulation is used to predict the IR spectra of the1:1 complexes with water and analyse the shifts expected for the micro-hydrated molecule.Graphical abstractGraphical abstract for this article
       
  • The theoretical study of electronic states with spin-orbit coupling of
           Zirconium monoxide
    • Abstract: Publication date: Available online 1 June 2019Source: Computational and Theoretical ChemistryAuthor(s): J. Tabet, Z. Adem, F. Taher The theoretical studies of the electronic structure of ZrO molecule to predict the molecular characteristics and the spectroscopic constants are performed with Ab-initio methods, the (MRCI-SD)/CASSCF. The configuration interaction (CI) method which employed consistent basis sets with effective core potentials for Zr atom, determined 13 singlet and 11 triplet low-lying electronic states below 38600 cm-1. 7 new singlet and 6 new triplet states not yet observed, are calculated for the first time. In addition to the electronic energy Te referred to the ground state energy at equilibrium, for the states presented as2S+1Λ±, we computed the spectroscopic constants including ωe, Re, the permanent electric dipole moments and the transition dipole moments (TDM). We are also reporting 47 electronic components in the representation Ω(±) below 38600 cm-1, when calculating the spin orbit effects. These calculated energies and spectroscopic constants are in excellent agreement with the previous experimental and theoretical results.Graphical abstractGraphical abstract for this article
       
  • Effect of heterocyclic spacer on property of hole-transporting materials
           with silafluorene core for perovskite solar cells
    • Abstract: Publication date: Available online 1 June 2019Source: Computational and Theoretical ChemistryAuthor(s): Zemin Zhang, Rongxing He Three hole-transporting molecules S-O, S-S and S-Se are designed through introducing heterocyclic spacers into the silafluorene core of S101. The effects of heterocyclic spacer on the geometry, electronic property and hole mobility of these materials are investigated systematically through using the DFT, Marcus formula and Einstein relation. The HOMO energy levels of S-O, S-S and S-Se are lower than that of S101 from calculated results, indicating that introduction of heterocyclic spacer can improve the open circuit voltage of device. Further, all of the designed molecules with heterocyclic spacer have larger electronic coupling relative to S101 because of more efficient intermolecular π-π stacking and interactions, which makes their hole mobility be higher than that of S101. The hole mobility will decrease gradually with the increase of heteroatom number. That is, the way introducing heterocyclic spacer into the silafluorene core of hole-transporting materials can enhance the hole transfer ability. The present theoretical investigation provides a meaningful way for improving the hole transport property of silafluorene-based materials.Graphical abstractGraphical abstract for this article
       
  • Analytic treatment of IR-spectroscopy data for double well potential
    • Abstract: Publication date: Available online 31 May 2019Source: Computational and Theoretical ChemistryAuthor(s): A.E. Sitnitsky A theoretical scheme for the analysis of experimental data on IR spectroscopy for a quantum particle in a double well potential (DWP) is suggested. The analysis is based on the trigonometric DWP for which the exact analytic solution of the Schrödinger equation is available. The corresponding energy levels along with their wave functions are expressed via special functions implemented in Mathematica (spheroidal function and its spectrum of eigenvalues). As a result trigonometric DWP makes the calculation of the energy levels an extremely easy procedure. It contains three parameters allowing one to model the most important characteristics of DWP (barrier height and the distance between the minima of the potential) along with the required asymmetry. Our approach provides an accurate calculation of the energy spectrum for hydrogen bonds in chromous acid (CrOOH) and potassium dihydrogen phosphate (KH2PO4) along with their polarizability in agreement with available experimental data.Graphical abstractGraphical abstract for this article
       
  • Introduction of Polar or Nonpolar Groups at the Hydroquinone Units Can
           Lead to the Destruction of the Columnar Structure of Pillar[5]arenes
    • Abstract: Publication date: Available online 31 May 2019Source: Computational and Theoretical ChemistryAuthor(s): Xiao Wang, Rui-xue Chen, Andrew C.-H. Sue, Han Zuilhof, Adelia J.A. Aquino, Hans Lischka Pillar[5]arenes, a type of novel macrocycles containing di-substituted hydroquinone units linked by methylene bridges in para-positions, have attracted extensive attention in supramolecular chemistry as interesting candidates to be used in the preparation of host-guest complexes. Functionalization by means of rim substitution and sustaining an ordered substituent arrangement on both sides of the rim is important for the development of new pillararene-based materials. In order to achieve this, the rim inversion process of rotating the hydroquinone units through the pillar[5]arenes has to be controlled. In this context we have studied the effect of different types of hydroquinone substituents on the rotational energy profile using density functional theory combined with the hybrid M06-2X functional. The influence of polar (-CH2F, -CH2Cl, -CH2OH, -CH2SH, -CH2NH2) and nonpolar alkyl (-CH3, –CH2CH3, –CH2CH2CH3, -CH(CH3)2, and –CH2CH2CH2CH3) substituents on the on the energy barriers of the rotation mechanism, and different local minima was investigated. The stabilization of the intermediate structures by non-covalent van der Waals and interactions and also by hydrogen bonds constitute a major factor affecting barrier heights. In case of polar substituents, the largest barriers were found for -CH2OH and -CH3 substitutions and the lowest ones for -CH2SH and -CH2NH2. For the alkyl series, the barrier decreased significantly up to propyl due to increasing stabilizing dispersion interactions while it increased again for n-butyl since the chain did not fit in well the cavity to rotate through.Graphical abstractGraphical abstract for this article
       
  • Excited State Dynamics initiated by an Electromagnetic Field within the
           Variational Multi-Configurational Gaussian (vMCG) method
    • Abstract: Publication date: Available online 30 May 2019Source: Computational and Theoretical ChemistryAuthor(s): T.J. Penfold, M. Pápai, K.B. Møller, G.A. Worth The Variational Multi-Configurational Gaussian (vMCG) approach offers a framework to perform exact trajectory-based quantum dynamics. Herein we use two model vibronic coupling Hamiltonians of pyrazine to explore, for the first time, the influence of the coupling between the external field and the Gaussian basis functions (GBFs) in vMCG on the dynamics. We show that when the excitation pulse is short compared to the nuclear dynamics, vertical projection without a field and explicit description of the external field converge. For longer pulses, a sizeable change is observed. We demonstrate that comparatively few GBFs are sufficient to provide qualitative agreement to MCTDH dynamics and a quantitative agreement can be achieved using ∼100 GBFs. Longer pulses require more GBFs due to the prolonged coupling between the ground and excited states. Throughout this work the single set formalism offers the fastest convergence.
       
  • Exploring the Electronic Structure and Stability of HgF6: Exact
           2-Component (X2C) Relativistic DFT and NEVPT2 Studies
    • Abstract: Publication date: Available online 25 May 2019Source: Computational and Theoretical ChemistryAuthor(s): Chun Gao, Shu-Xian Hu, Huixian Han, Guina Guo, Bingbing Suo, Wenli Zou As a group 12 element, mercury locating at the sixth row with a valent electronic configuration of 5d106s2 has been treated as a main group element featuring +I and +II oxidation states for a long time. C. K. Jørgensen conjectured the existences of HgF4 and HgF6 molecules in early 1960s, where HgF4 was first synthesized in 2007, but HgF6 as the Hg(+VI) compound was less known. In this paper we explored the electronic structure and decomposition paths of HgF6 by scalar (X1C) and 2-component relativistic (X2C) density functional calculations and more accurate multi-reference NEVPT2 calculations. It is found that the HgF6 molecule, where the mercury atom presents an extraordinary high oxidation state of +VI, is protected by a considerable barrier height of about 22 kcal/mol for the decomposition into HgF4 and two isolated fluorine atoms. The results propose that HgF6 is kinetically stable and may exist under exorbitant conditions.Graphical abstractGraphical abstract for this article
       
  • On the interaction of propynal with HNO, HF, HCl, H2O, CH3OH, and NH3:
           Red- and blue-shifting hydrogen bonds and tetrel bonds
    • Abstract: Publication date: Available online 22 May 2019Source: Computational and Theoretical ChemistryAuthor(s): Alfred Karpfen The potential energy surfaces of the complexes of propynal, (propiolaldehyde, propargyl aldehyde, HCCCOH), with a series of small molecules (HNO, HF, HCl, H2O, CH3OH, and NH3) have been investigated theoretically at the MP2 and CCSD(T) levels using several extended basis sets. Thirty low-lying minima have been detected, eight for HCCCOH-HNO, four for each of the dimers HCCCOH-HF, HCCCOH-HCl, and HCCCOH-H2O, seven for the HCCCOH-CH3OH complex, and three for HCCCOH-NH3. The most stable HCCCOH-HNO complex has a non-planar, orthogonal structure with a tetrel bond and a hydrogen bond. In most cases the calculated intramolecular bond length changes as induced by complex formation are allegeable on the basis of the intramolecular harmonic force fields of propynal and the partner molecules. The vibrational frequency shifts, typical for formyl groups engaged in hydrogen bonding, red shifts of C=O stretches and blue shifts of C-H stretches, occur in most of the dimers, whereas the acetylenic C-H and C≡C stretches are red-shifted when this C-H bond is involved in hydrogen bonding. In almost all HCCCOH-HNO complexes, the N–H stretching frequency is also blue-shifted. However, in case of the most stable HCCCOH-HNO complex a red-shift of the harmonic N-H stretch is calculated. Inclusion of anharmonic contributions reduces this red shift substantially and even converts it to a blue shift. Conventional red shifts of X-H (X=F, Cl, O) stretching frequencies and blue shifts for formyl C-H stretches are calculated for most of the complexes with HF, HCl, H2O, CH3OH, and NH3.Graphical abstractGraphical abstract for this article
       
 
 
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