metal surface with atomic / molecular interactions of first-principles calculations

Title: metal surface with atomic / molecular interactions of first-principles calculations Authors: Bo Sun Degree awarded: China Academy of Engineering Physics Keywords: first - principle of the calculation;; quantum size effect;; surface of the initial oxidation;; molecular dissociation barrier;; plutonium oxides Abstract: This paper based on density functional theory (DFT) first-principles calculations to study the metal film surface and atoms or molecules
Microscopic interaction mechanisms. Magnetic lifter The main contents include three parts: First, quantum size effects in metal films (QSE) and its impact on surface forces can learn
Volume and modulation of chemical reactions; the second is the initial oxidation of the metal surface; last used to calculate the DFT + U method, and strongly correlated materials PuO_2
Pu_2O_3 the ground state electronic structure. In the first part, the third, the two chapters work were calculated Cu (001)
And Pb (111) thin film quantum size effects. The third chapter, we have the thickness from 1-26 atomic monolayer (ML) of the clean Cu (001)
The film launched the system first-principles calculations. Detailed discussion of the Brillouin zone corresponding to the extreme point of a certain quantum state, given
Cu (001) thin film electronic structure, surface energy, electronic work function, interlayer relaxation with the film thickness and other physical changes in the quantum oscillation line
Is. We also discussed the Cs atoms in the Cu (001) surface adsorption properties, gives the adsorption energy and local electronic density of states with the film
Thickness changes in the relationship, reflecting the Cu (001) thin film quantum size effects. The study found that as precious metals Fermi unique "neck
"Track and" belly "orbit quantum interference, making the Cu (001) films on the surface stability, chemical activity and chemical reaction was
Emerged in the length of cycle (2.7ML http://www.999magnet.com/products/131-magnetic-lifter and 5.6ML) the complexity of coupled oscillatory behavior. Chapter IV, we calculated the clean and 3d-
Single magnetic atom (Cr, Mn, Fe and Co) adsorption of Pb (111) films the amount of force can learn, electronic structure and spin magnetic moments and other properties with film
Thickness (1-18ML) changes in behavior. Atom adsorption energy increases with film thickness show films with clean, consistent surface energy of the quantum
Oscillating trend, reflecting the adsorption energy of the quantum size effect. Cr, Mn atoms can be closer to the adsorption, significantly less than the case of Fe and Co.
Cr and Mn adsorption, the system of total spin magnetic moment to show films with clean surfaces can reverse the trend of the oscillation, which stems from the Pb (111) Table
6p surface conduction electron spin polarization of the quantum oscillations. The adsorption of Fe and Co, the system is the total magnetic moment changes with film thickness
Of erratic. Adatom interaction with the surface according to the strength of adsorption and surface-conduction electron-magnetic shielding effect of the atomic oscillation line
Is, we theoretically predict Cr, Mn atoms in the Pb (111) film on the metal film Kondo effect will be the tone of the quantum size effect
System. The second part of the content, Chapters 5 and 6, respectively, the two working systems studied two types of metal surface Pb (111) and Be (0001)
The initial surface oxidation. For Pb (111) surface of the initial oxidation, we emphasize the O_2 dissociation of O atoms with the metal surface after the phase
Interaction, the system studied to 1ML from 0.11 ML coverage of O atoms within the Pb (111) surface and subsurface adsorption properties; calculation
The O atoms on the surface and sub-surface diffusion energy barrier, and O atoms from the surface to subsurface penetration barrier. The entire range of coverage
the fcc site, and tetra-Ⅱ were O on the surface and subsurface adsorption of the best locations. O atoms in the best position of the binding energy of adsorption, along with the
Coverage increases monotonically increasing, meaning that O atoms adsorbed mutual attraction exists between the effective interaction, tends in the Pb (111) surface and sub-
Surface clusters. In the entire coverage range, O adatom in the Pb (111) sub-surface adsorption is more stable. O atoms in Pb
(111) surface and sub-surface diffusion barrier significantly affected by the coverage, with the increase of coverage. We found that when low-coverage O
Bit from the surface to the sub-surface hcp tetra-Ⅰ bit penetration barrier of only 0.065 eV. That O_2 in the Pb (111) surface after the decomposition, even in the
Under low O coverage will be very easy to penetrate into the sub-surface coupling with the second layer of Pb atoms bond. Our O / Pb (111) adsorption system other
Calculate in detail the nature of the discussion, including the charge redistribution, the atomic structure of the layer relaxation, work function and electron density of states, we
Found in Pb (111) surface oxidation in O-Pb bond with ions - a total price of phase-mixed characteristics: ion is reflected in the Pb-6p electronic
To the O-2p orbital transfer; and the performance of covalent electrons in the Pb lost 6p, Pb-6s ~ 2 lone pair electrons with the O-2p hybridization of electronic states.
For Be (0001) surface oxidation, we focus on point of view O_2 in the Be (0001) surface and adsorption properties of the decomposition process. The results distinguish between the
The O_2 physical and chemical adsorption states, respectively, in parallel to the surface and perpendicular to the surface of the channel. We analyzed the most stable elements of
Adsorption of state (HH-Z-channel) of the electronic structure and found that the anti-bonding state O_2 π_p ~ * molecular orbital electron spin on the surface of Be atoms to the empty state of the transfer
Shift, and surface state electron of Be atoms occupy anti-bonding state O_2 π_p ~ * molecular orbital spin state feed under the null, while O_2 and Be (0001)
Obvious between the surface atoms of covalent bond. Such as by calculating the adiabatic potential energy surface to determine the O_2 in the Be (0001) surface dissociation path, find
TY along O_2 dissociation channel is the best channel, the dissociation energy barrier is 0.23 eV. In simple sp-metal surface oxidation of work,
We first reported the O_2 decomposition theory, there is insulation barrier. Finally, we DFT + U theory framework, and on PuO_2
β-Pu_2O_3 ferromagnetic, antiferromagnetic and non-magnetic system launched three structures calculated. We found that LDA + U and GGA + U (U = 4 eV) can
Improve the traditional density functional theory calculations, and experimental results are given to match the electronic structure of Pu oxides, and confirm PuO_2 and β
-Pu_2O_3 antiferromagnetic ground state of nature. The U parameter considerations prompted Pu-5f electrons at the Fermi level splitting occurs, leading to a
Metal - insulator transition, and two kinds of plutonium oxide insulator gap increases with the U parameter. In addition, we calculated the β-Pu_2O_3 to
PuO_2 oxidation reaction can be revealed that the oxidation process is an exothermic process, with the experimentally observed self 150-200 ℃ Pu
Phenomenon corresponds to the burning. Degree Year: 2009