Redistribution Of Electron Density Research Articles

Influence of the Support on the Catalytic Characteristics of the Deposited Palladium in the Liquid-Phase Hydrogenation of Diphenylacetylene

Palladium catalysts on various types of supports were studied in the liquid-phase hydrogenation of diphenylacetylene. Samples of Pd/SiO2–Al2O3, Pd/MgAl2O4, Pd/Al2O3, and Pd/TiO2 were characterized by the chemisorption of the CO and IR spectroscopy of adsorbed CO. The use of n-hexane as the solvent increases the reaction rate, which can be explained by the better solubility of hydrogen in the liquid phase. It is established that the acid–base properties of the support do not affect the activity and selectivity of the catalysts in the reaction under study. However, they alter the electronic state of palladium. According to the catalytic tests, Pd/TiO2 has the highest activity (turnover frequency) and selectivity to alkene. The comparison of the obtained catalytic data and the results of IR spectroscopy made it possible to conclude that this is due to the electron density redistribution between the palladium and TiO x particles, which is caused by the strong metal–support interaction.

BET & ELF Quantum Topological Analysis of Neutral 2-Aza-Cope Rearrangement of γ-Alkenyl Nitrones.

The 2-Aza-Cope rearrangement of γ-alkenyl nitrones is a rare example of the neutral thermal 2-aza-Cope process that usually takes place with cationic species. During the rearrangement, a redistribution of bonds and electronic density occurs in one kinetic step. However, the introduction of substituents with different steric requirements and electronic features might alter the activation energies and the synchronicity of the reaction. The electron localization function (ELF) analysis and its application to Bonding Evolution Theory (BET) analysis within the context of Molecular Electron Density Theory (MEDT) is an excellent tool to monitor the electron density along the reaction coordinate and thus investigate in detail bond breaking and formation and the corresponding energy barriers. By analyzing topological ELF calculations of seventeen 2-aza-Cope nitrone rearrangements with selected substituents, the main factors influencing the synchronicity of the process were investigated. This MEDT study results revealed that the rearrangement is a non-polar process mostly influenced by steric factors rather than by electronic ones, and confirms the pseudoradical character of the process rather than any pericyclic electron-reorganization.

Interactions between copper and transition metal dichalcogenides: A density functional theory study

We characterized the interface between fcc Cu and various single-layer transition metal dichalcogenides (TMDs) using density functional theory calculations. We found that monolayer Mo, W, Nb, Ti, and V disulfides, diselenides, and ditellurides are stable on Cu(111) with binding energies higher than those of $h$-BN and graphene. An analysis of the electronic structure of the interfaces indicates partial covalent bonding and a complex redistribution of electronic density, consisting of electron accumulation in the gap region, depletion near the Cu and TMD surfaces, and charge density oscillations within both materials. The resulting net electric dipoles significantly alter the electron work function of the Cu surface. Interestingly, capping Cu(111) surfaces with group-IV and -V TMDs leads to an increase in the work function of up to 1 eV, while group-VI TMDs can decrease the work function by up to 1 eV. Finally, the complex charge distributions at the Cu/TMD interfaces include opposing dipoles and explain the fact that net dipoles associated with Cu/TMD interfaces are comparable to or smaller than those of Cu/graphene and Cu/$h$-BN, even though the Cu/TMD binding energies are significantly higher.

Theoretical Insights on Solvent Control of Intramolecular and Intermolecular Proton Transfer of 2-(2′-Hydroxyphenyl)benzimidazole

Excited-state proton transfer (ESPT) processes of 2-(2'-hydroxyphenyl)benzimidazole (HBI) and its complexation with protic solvents (H2O, CH3OH, and NH3) have been investigated by both static calculations and dynamics simulations using density functional theory (DFT) at B3LYP/TZVP theoretical level for ground state (S0) and time-dependent (TD)-DFT at TD-B3LYP/TZVP for excited state (S1). For static calculations, absorption and emission spectra, infrared (IR) vibrational spectra of O-H mode, frontier molecular orbitals (MOs), and potential energy curves (PECs) of proton transfer coordinate were analyzed. Simulated absorption and emission spectra show an agreement with available experimental data. The hydrogen bond strengthening in the S1 state has been proved by the changes of IR vibrational spectra and bond parameters of the hydrogen moiety with those of the S0 state. The MOs provide the visual electron density redistribution confirming the hydrogen bond strengthening mechanism. The PECs show that the proton transfer (PT) process is easier to occur in the S1 state than the S0 state. Moreover, on-the-fly dynamics simulations of all systems were carried out to provide the detailed information on time revolution. The results revealed that the excited-state intermolecular proton transfer for HBI is fast, whereas the excited-state intermolecular proton transfer for HBI with protic solvents are slower than that of HBI because the competition between intra- and intermolecular hydrogen-bonds between HBI and protic solvent. These intermolecular hydrogen-bonds hinder the formation of tautomer, hence explaining the low quantum yield found in the protic solvent experiment. Especially for HBI complexing with methanol, only ESIntraPT occurs with small probability compared to HBI with water and ammonia.

A confinement induced spectroscopic study of noble gas atoms using equation of motion architecture: Encapsulation within fullerene's voids.

A relativistic study of spectroscopic properties of the endohedral fullerenes Ng@C60q (where Ng = He, Ne and q=0,±1,±2 are the charges) associated with the C60 molecule has been done using the equation of motion coupled cluster (EOM-CC) methodology. Specific properties estimated are the transition energies, dipole oscillator strengths, and transition probabilities for the low-lying excitations 1s2(1S0) → 1snp (1P1) (n = 2, 3, 4) for He@C60q and 1s22s22p6 (1S0) → 1s22s22p5ns∕nd (1P1) (n = 3, 4) for Ne@C60q, which have been compared with those for the isolated atom to depict the confinement effect of the host molecule on the encapsulated atom. This is accomplished by introducing an effective potential to the atomic Hamiltonian induced by the fullerene moiety and its charge. The EOM-CC results have been compared with those estimated with the random phase approximation (and configuration interaction singles) to understand the effect of electron correlation under such confinement. The systematic and interesting behavior of the properties is highlighted indicating the effect of fullerene cage potential on the redistribution of electron density of the guest atom.

Study on Photophysical Properties of N-Arylphthalamic Acid Derivative Containing 1, 2, 4-Triazole Scaffold.

A novel N-arylphthalamic acid derivative, 2-({4-[(1H-1,2,4-triazol-1-yl)methyl]phenyl}carbamoyl)benzoic acid (TMPCB) was synthesized and their absorption and emission spectra were recorded in fifteen different solvents of varying polarities at room temperature. Ground state dipole moment of the derivative was calculated experimentally by Guggenheim method and solvatochromic approach proposed by Bilot-Kawski. The singlet excited state dipole moment of TMPCB were calculated experimentally based on different approaches of solvent polarity function proposed by Lippert-Mataga, Bakhshiev, Kawskii-Chamma-Viallet, Reichardt and Bilot-Kawski. Singlet excited state dipole moment was greater than ground state dipole moment in all the approaches which could be attributed to considerable π- electron density redistribution. Multiple Linear Regression (MLR) analysis based on Kamlet-Abboud-Taft and Catalan parameters were also studied to correlate solvatochromism and influence of solvents with absorbance and emission spectra. Ground and singlet excited state optimizations of the molecule were also performed using Gaussian 09W software. HOMO-LUMO energies of the phthalamic acid derivative have been obtained using TD-DFT/PCM (B3LYP/6-31G (d, p)) computations and experimentally by using cyclic voltammetry. Mulliken charges and molecular electrostatic potential plot have also been generated from DFT calculations to identify nucleophilic and electrophilic sites of TMPCB.

Evolution in Time of Radiation Defects Induced by Negative Pions and Muons in Crystals with a Diamond Structure

Evolution in time of radiation defects induced by negatively-charged pions and muons in crystals with diamond structures is considered. Negative pions and muons are captured by the nucleus and ionize an appropriate host atom, forming a positively-charged radiation defect in a lattice. As a result of an evolution in time, this radiation defect transforms into the acceptor center. An analysis of the full evolution process is considered for the first time. Formation of this acceptor center can be divided into three stages. At the first stage, the radiation defect interacts with a radiation trace and captures electrons. The radiation defect is neutralized completely in Si and Ge for a short time t ≤ 10 − 11 s, but in diamond, the complete neutralization time is very large t ≥ 10 − 6 s. At the second stage, broken chemical bonds of the radiation defect are restored. In Si and Ge, this process takes place for the neutral radiation defect, but in diamond, it goes for a positively-charged state. The characteristic time of this stage is t < 10 − 8 s for Si and Ge and t < 10 − 11 s for diamond. After the chemical bonds’ restoration, the positively-charged, but chemically-bound radiation defect in diamond is quickly neutralized because of the electron density redistribution. The neutralization process is characterized by the lattice relaxation time. At the third stage, a neutral chemically-bound radiation defect captures an additional electron to saturate all chemical bonds and forms an ionized acceptor center. The existence of a sufficiently big electric dipolar moment leads to the electron capture. Qualitative estimates for the time of this process were obtained for diamond, silicon and germanium crystals. It was sown that this time is the shortest for diamond (≤ 10 − 8 s) and the longest for silicon (≤ 10 − 7 s)

Effects of Cr on H and He trapping and vacancy complexes in V in a fusion environment: a first-principles study

First-principles density functional theory was used to investigate the interaction between hydrogen (H) and helium (He) in V–Cr alloy, which is a potential structural material for use in fusion reactors. When vacancies are present in the V–Cr alloy, a single He atom prefers to occupy the octahedral site near the Cr atom rather than vacancy centre, which differs from the cases of iron and tungsten. Because of the decrease of the electron density around the He atom, there was a strong interaction between He and H. In the vicinity of He-vac complexes, H atoms tend to stay in the tetrahedral site rather than occupy the octahedral-interstitial site. A single He-vac complex can trap as many as six H atoms, which is more than can be trapped by an empty vacancy in the V–Cr alloy because of the electronic density redistribution of vacancy vicinity. This strong attraction explains the enhanced retention of H and He observed near the surface of V and V-based alloys under both sequential and simultaneous bombardments. The results provide useful insight into the application of the V-based alloys as candidate structural materials in fusion Tokamaks.

Filler's impact on structure and physical properties in polyester resin–oxide nanocomposites

Impact of nanosized oxide particles of titania (titanium dioxide, rutile) and silica–titania fumed compound on structure relaxation processes in nanocomposites of an orthophtalic unsaturated styrene cross-linked polyester resin has been experimentally studied using the thermal desorption mass spectroscopy, the dielectric spectroscopy, and the positron annihilation lifetime spectroscopy. All the nanocomposites showed unmonotonous variations in the thermal resistance, the dielectric permittivity and losses, and the annihilation rates for both positrons and ortho-positronium atoms with increasing filler’s loading. The nanoparticle-loading effects can be explained on the assumption that the oxide particles embedded into a cross-linked polyester resin induce rearrangements in its structure. Several mechanisms of particle–polymer interface interaction compete simultaneously and thus promote the alterations in molecular structure of the nanocomposites. The mechanisms may include both chemical and electrostatic fastening of polyester chains and styrene cross-links to the active surface sites, the destruction of the styrene cross-links, and redistribution of electron density in polymers. The features of the loading effects observed in the different nanocomposites can be ascribed to distinctions in both of active surface sites and intrinsic dielectric properties of the filling oxide particles.

Exploring fundamental differences between red- and blue-shifted intramolecular hydrogen bonds using FAMSEC, FALDI, IQA and QTAIM

We have discovered, using developed by us recently FALDI and FAMSEC computational techniques, fundamentally distinct mechanisms of intramolecular red- and blue-shifted H-bond formation that occurred in different conformers of the same molecule (amino-acid β-alanine) involving the same heteroatoms (O–H⋅⋅⋅N and N–H⋅⋅⋅O). Quantitative topological, geometric and energetic data of both H-bonds obtained with well-known QTAIM and IQA methodologies agree with what is known regarding H-bonding in general. However, the FALDI charge and decomposition scheme for calculating in real space 3D conformational deformation densities provided clear evidence that the process of electron density redistribution taking place on the formation of the stronger red-shifted H-bond is fundamentally distinct from the weaker blue-shifted H-bond. Contributions made by atoms of the X–H⋅⋅⋅Y–Z fragment (IUPAC notation) as well as distinct atoms on the H-bond formation were fully explored. The FAMSEC energy decomposition approach showed that the atoms involved in formation of the red-shifted H-bond interact in a fundamentally different fashion, both locally and with the remainder of the molecule, as compared with those of the blue-shifted H-bond. Excellent correlations of trends obtained with QTAIM, IQA, FAMSEC and FALDI techniques were obtained. Commentary regarding IUPAC recommended definition of an H-bond and validity of observed AILs (or bond paths) of the two H-bond kinds is also discussed.

IR spectroscopy studies of sodium salts of some aminobenzoic acid derivatives

Products of a reaction of four aromatic amino acids—para-aminobenzoic (p-ABA), ortho-aminobenzoic (o-ABA), methyl-bis-anthranilic (MBAA), and 4,6-diamino-isophthalic (DAPhA)—with sodium hydroxide have been studied by Fourier-transform IR spectroscopy. It has been shown that acid groups do not undergo complete conversion to salt groups because a decrease in the solution pH during reaction leads to a shift of the tautomeric equilibrium toward the formation of zwitterions. In the solid phase, the zwitterions remain in compounds in which they are present in the acids (MBAA and o-ABA) and appear in the DAPhA salt owing to the electron density redistribution in the aromatic ring. It has been found that the p-ABA salt molecules are in the canonical form. The formation of the salts leads to a change in the supramolecular organization of the molecules in the solid phase. The most energetically favorable intermolecular hydrogen bond of carboxylic acid dimers is replaced by the hydrogen bond between the oxygen atoms of the carboxylate anions and the protons of the amino groups.

A study of the exchangeable protons in the QA site of photosystem II

Plants have developed the only biological system capable of oxidizing water. Through the oxidation of water plants are able to convert light energy into chemical energy. This water oxidation is catalyzed by photosystem II (PSII) at a site called the oxygen‐evolving complex (OEC). The OEC consists of a tetranuclear manganese cluster and is the only known biological system capable of oxidizing water (Blakenship 2001).Removal of the manganese cluster allows for study of the mechanism called photoactivation, a light‐and dark‐dependent process by which the OEC assembles. Further study of this process can provide great detail as to repair of PSII following inhibition (G. Dismukes 2008). Removal of the manganese cluster and associated extrinsic proteins also allows unhindered exploration of electron transfer during photochemical events. Plastoquinone A (QA) and plastoquinone B (QB) are electron carriers found in PSII. Despite sharing the same molecular structure, QA and QB exhibit unique redox properties determined by their protein environment. QA participates only in one‐electron transfers, transiently forming paramagnetic semiquinone QA−•(SQA), whereas QB function as a two‐electron gate. Hydrogen bonding from nearby amino acids residues is believed to be partly responsible for such differences in redox properties due to redistribution of electron density. High‐resolution electron paramagnetic resonance (EPR) spectroscopy has the ability to measure magnetic interactions between unpaired electrons and nearby nuclei and provide information about the strength of these interactions (Rutherford, A. W. 1999).Previous pulsed EPR studies established the formation of the H‐bonds between carbonyl oxygens of the QA−• and an amide nitrogen from the protein backbone, and the amino nitrogen, Nd, of an imidazole (Rutherford; Lakshmi). Two‐dimensional pulsed EPR of the SQA in Mn depleted, CN‐treated PSII at pH 9.8, resolved five pairs of cross‐peaks from different types of protons (Lakshmi). They were assigned to the methyl, β‐methylene, and ring protons of the SQA and two protons of the H‐bonds. Unfortunately, these assignments were not verified by the influence of 1H2O/2H2O exchange on the spectra. As a consequence, the assignment of the couplings is not consistent with the values obtained in the DFT calculations (T.‐J. Lin and P. J. O'Malley 2011). In this work we performed 2D pulsed EPR with the SQA in the PS II samples in 1H2O and 2H2O buffered solution in order to unambiguously identify contribution of the exchangeable protons and to determine corresponding hyperfine couplings. These results form a more supported basis for comparison with the results of theoretical computations.Support or Funding InformationPulsed EPR studies were supported by DE‐FG02‐08ER15960 Grant from Chemical Sciences, Geosciences and Biosciences Division, Office of Basic Energy Sciences, Office of Sciences, US DOE (S.A.D.), and NCRR/NIH Grants S10‐RR15878 and S10‐RR025438 for pulsed EPR instrumentation. Continuous wave EPR studies were supported by NSF‐MRI CHE‐1229498.

Understanding the electron-phonon interaction in polar crystals: Perspective presented by the vibronic theory

We outline our novel results relating to the physics of the electron-TO-phonon (el-TO-ph) interaction in a polar crystal. We explained why the el-TO-ph interaction becomes effectively strong in a ferroelectric, and showed how the electron density redistribution establishes favorable conditions for soft-behavior of the long-wavelength branch of the active TO vibration. In the context of the vibronic theory it has been demonstrated that at the macroscopic level the interaction of electrons with the polar zone-centre TO phonons can be associated with the internal long-range dipole forces. Also we elucidated a methodological issue of how local field effects are incorporated within the vibronic theory. These result provided not only substantial support for the vibronic mechanism of ferroelectricity but also presented direct evidence of equivalence between vibronic and the other lattice dynamics models. The corresponding comparison allowed us to introduce the original parametrization for constants of the vibronic interaction in terms of key material constants. The applicability of the suggested formula has been tested for a wide class of polar materials.

Synthesis and spectral properties of near-IR polymethine dyes derived from tris(2,2,3,3,4,4,5,5-octafluoropentyl)-9H-fluorene-2,4,7-trisulfonate

A vinylogous series of anionic polymethine (cyanine) dyes has been synthesized based on tris(2,2,3,3,4,4,5,5-octafluoropentyl)-9H-fluorene-2,4,7-trisulfonate. It has been found that their longest-wavelength and most intense electronic transition has the polymethinic origin, unlike the analogous polynitrofluorene dyes. As established, the corresponding absorption band, in contrast to that of classical cyanines, remains quite intense and narrow in the near-IR spectral region even in highly polar solvents. The nature of electronic transitions and relevant molecular orbitals as well as excitation-induced electron density redistributions have been studied by the DFT and TDDFT methods at the CAM-B3LYP/6-31G(d,p) level.

Topological analysis of steric and relaxation deformation densities

ABSTRACTSteric and relaxation as components of deformation density are characterised by topological analysis; and critical points are found as important descriptors for interatomic and intermolecular interactions. In this respect, repulsive and attractive types of electron density redistribution can be examined distinctly, with their own critical points. The steric component as repulsive interaction is appeared as a local minimum critical point, while relaxation component as attractive component appears as a local maximum in the Cartesian space. The formalism is applied to extensively different complexes including closed- and open-shell interactions, and the results fairly agree with chemical interpretation of these two types of interactions.

Reproduction and interpretation of the UV–vis spectra of some flavonoids

The UV–vis spectra of 15 naturally occurring flavonoids, including flavones, flavonols, and isoflavones, were simulated and compared to literature experimental results. For this purpose, the TDDFT method in conjunction with the B3LYP-D3 and B3LYP functionals was applied. In spite of some discrepancy between the structural predictions, the differences between the TDDFT/B3LYP and TDDFT/B3LYP-D3 results are negligible. The performance of both functionals in reproducing the UV–vis spectra of the selected flavonoids is satisfactory. The NLMO clusters, i.e. molecular moieties characterised with distinguished electron density, were created. The combined results from the TDDFT and NLMO approaches were employed to perform deep analysis of the spectra. It was found that the transitions from the bonding NLMO clusters to the LUMO cluster are favoured at longer wavelengths, whereas the transitions from the HOMO and HOMO−1 clusters to the antibonding NLMO clusters are favoured at shorter wavelengths. All flavonoids show the HOMO → LUMO and HOMO−1 → LUMO transitions at long wavelengths, and majority of them show the HOMO → LUMO+1 transition at moderate wavelengths. This investigation confirms our earlier finding that the TDDFT and NBO approaches are complementary, implying that the results from the two theories can be combined to better understand the redistribution of electron density upon excitation.

Towards understanding the strong trapping effects of noble gas elements on hydrogen in tungsten

We have investigated the effects of noble gas elements (helium, neon, argon and krypton) on the dissolution and accumulation behavior of hydrogen (H) in tungsten (W) using a first-principles method, as well as the behaviors of themselves. Noble gas atoms energetically prefer to occupy the tetrahedral interstitial site (TIS) in W, as the same of H. The TIS → TIS is their optimal diffusion path, and the diffusion energies increase with the increasing of atomic radius. All of them are energetically favorable clustering by self-trapping. It is found that the presence of the noble gas elements have significant effect on H behavior in W. Both interstitial noble gas atoms and their complex with vacancy can serve as strong trapping centers of H, which can be attributed to the redistribution of electron density and lattice distortion induced by noble gas. Most importantly, we have demonstrated that H trapping capability of noble gas clusters will increase with the increasing of the number of noble gas atoms in both interstitial and vacancy-complex cases. The H trapping energy surrounding the noble gas clusters with four atoms is comparable to that in noble gas-free vacancy. Further, the formation of noble gas clusters is much easier than that of vacancy due to the self-trapping interaction between noble gas atoms (>1 eV for interstitial case and >4 eV for vacancy-complex case), and thus the H trapping centers will rapidly increase after noble gas pre-irradiation/implantation. Consequently, the self-trapping character of noble gas induces their strong trapping effect on H.

ELECTRONIC STRUCTURE AND PROPERTIES OF APATITE-LIKE CALCIUM-BASED COMPOUNDS, INITIATED BY NANODIMEMSION, BIOGENIC FACTOR AND ISOMORPHIC SUBSTITUTION OF CALCIUM BY 3D-METALLS

Calcium apatites due to their physicochemical properties, high biological activity deservedly attract special attention not only in view of purely scientific interest, but also in connection with the use of drugs synthesized on their basis. in practical traumatology. dentistry, i.e. in those areas of medicine that are relevant to the treatment and restoration of bone tissue. As a rule, the basic elements are samples of nanometric dimensions. Electronic properties, features of chemical bond, structural parameters demonstrate high sensitivity to size reduction. In this paper, the nature of chemical bond, redistribution of electron density in energy and real space, isomorphically substituted hydroxyapatites based on calcium are studied with the complex application of such methods as photoelectron and X-ray spectroscopy, nuclear magnetic resonance, atomic force spectroscopy.

Intermolecular interactions in molecular crystals: what's in a name?

Structure-property relationships are the key to modern crystal engineering, and for molecular crystals this requires both a thorough understanding of intermolecular interactions, and the subsequent use of this to create solids with desired properties. There has been a rapid increase in publications aimed at furthering this understanding, especially the importance of non-canonical interactions such as halogen, chalcogen, pnicogen, and tetrel bonds. Here we show how all of these interactions - and hydrogen bonds - can be readily understood through their common origin in the redistribution of electron density that results from chemical bonding. This redistribution is directly linked to the molecular electrostatic potential, to qualitative concepts such as electrostatic complementarity, and to the calculation of quantitative intermolecular interaction energies. Visualization of these energies, along with their electrostatic and dispersion components, sheds light on the architecture of molecular crystals, in turn providing a link to actual crystal properties.

Influence of single axis strain on site occupation and diffusion of hydrogen atom in α-Fe

As is well known, hydrogen plays an important role in degrading mechanical properties of steel due to hydrogen embrittlement behavior. Thus, much attention should be paid to the interaction between hydrogen atom and Fe matrix especially in theoretical calculation and mechanism study. In this paper, the site occupations of hydrogen atom under different single axis strains in interstitial of α-Fe atoms are studied by the first principles calculation based on the spin-polarized density functional theory. The Kohn-Sham equations are solved under periodic boundary conditions, by using revised Perdew-Burke-Ernzerhof version of the generalized gradient approximation to account for the electron exchange and correlation. The total energy of the steady state crystal, binding energy, solution energy, density of states, charge density difference and charge population are calculated. The analyses of solution energy and density of states indicate that the hydrogen atom preferentially occupies the tetrahedral interstitial of α-Fe atoms under different single axis strains. With increasing tensile strain or reducing compressive strain, hydrogen atom prefers to occupy the site of tetrahedral interstitial. The analyses of charge population and charge density difference reveal that the hydrogen atom collects charges from Fe atoms, leading to electron density redistribution. The tensile strain reduces the charge transfer slightly while the compressive stress promotes the transfer process. The LST/QST (linear synchronous transit/quadratic synchronous transit) transition state search method is used to investigate the diffusion of hydrogen atom between two tetrahedral interstitials along the direction perpendicular to strain. Diffusion of hydrogen atom goes through transition state where the hydrogen atom is coordinated at octahedral interstitial. The minimum energy pathway for hydrogen diffusion under strainless state indicates the diffusion activation energy with a value of 0.58 eV. It is noticeable that the diffusion activation energy and the strain conforms to linear relation and are consistent with the fitting formula, Q=0.508+2.6ε. The diffusion activation energy increases with reducing compressive strain or increasing tensile strain. According to the calculation process and analysis results, we introduce the interaction between hydrogen atom and α-Fe at a level of electronic structure systematically and figure out the diffusion of hydrogen influenced by different states of stress.