osp(1∣2)osp(1|2) off-shell Bethe ansatz equation with boundary terms

This work is concerned with the quasi-classical limit of the boundary quantum inverse scattering method for the $osp(1|2)$ vertex model with diagonal $K$-matrices. In this limit Gaudin's Hamiltonians with boundary terms are presented and diagonalized. Moreover, integral representations for correlation functions are realized to be solutions of the trigonometric Knizhnik-Zamoldchikov equations.Comment: 38 pages, minor revison, LaTe

The algebraic Bethe ansatz for open vertex models

We present a unified algebraic Bethe ansatz for open vertex models which are associated with the non-exceptional $A^{(2)}_{2n},A^{(2)}_{2n-1},B^{(1)}_n,C^{(1)}_n,D^{(1)}_{n}$ Lie algebras. By the method, we solve these models with the trivial K matrix and find that our results agree with that obtained by analytical Bethe ansatz. We also solve the $B^{(1)}_n,C^{(1)}_n,D^{(1)}_{n}$ models with some non-trivial diagonal K-matrices (one free parameter case) by the algebraic Bethe ansatz.Comment: Latex, 35 pages, new content and references are added, minor revisions are mad

SU(N) Evolution of a Frustrated Spin Ladder

Recent studies indicate that the weakly coupled spin-1/2 Heisenberg antiferromagnet with next nearest neighbor frustration supports massive spinons when suitably tuned. The straightforward SU(N) generalization of the low energy ladder Hamiltonian yields two independent SU(N) Thirring models with N-1 multiplets of massive ``spinon'' excitations. We study the evolution of the complete set of low-energy dynamical structure factors using form factors. Those corresponding to the smooth (staggered) magnetizations are qualitatively different (the same) in the N=2 and N>2 cases. The absence of single-particle peaks preserves the notion of spinons stabilized by frustration. In contrast to the ladder, we note that the N=infinity limit of the four chain magnet is not a trivial free theory.Comment: 10 pages, RevTex, 5 figures; SU(N) approach clarifie

Photocatalytic Water Oxidation at the GaN (101̅0)−Water Interface

Domen has observed that the GaN/ZnO semiconductor alloy serves, in the presence of a sacrificial electron scavenger, as a photocatalyst for solar water oxidation, producing H+ and O2 at the aqueous/semiconductor interface. With a suitable cocatalyst, the same solar photoexcitation process also generates H2 from H+. The active sites, mechanisms, and reaction intermediates are not known. This paper describes atomistic modeling and proposes a sequence of intermediate steps for the water oxidation process at a pure GaN/water interface. Pure GaN is known to be photocatalytically active but only in the UV region, because the semiconductor band gap is 3.4 eV, outside the visible region of the spectrum. However, it serves as an appropriate model system in the absence of more detailed information. A flat (1017macr;0) nonpolar surface is chosen to model an active site. Ab initio molecular dynamics simulations examine the fully solvated aqueous interface at ambient temperature. An appropriate cluster model, that includes a polarizable continuum in addition to explicit solvent water molecules, is cut out from snapshots of these AIMD simulations for additional DFT-based calculations of the water oxidation mechanism. The reaction intermediates follow a sequence of four proton-coupled electron transfers. Four UV photons are consumed to generate the four photoholes which drive the oxidation, producing 4H+ + O2 from 2H2O. Calculated standard free energies show that the photogenerated holes in GaN have sufficient energy to drive the overall water oxidation reaction. Implications for the operation of GaN/ZnO alloy photocatalysts, which absorb in the visible wavelength range, are presented. The calculated potentials show a remarkable parallelism to the known potentials for the sequential one-electron oxidation of water in homogeneous aqueous solution, suggesting that the proposed sequence may apply more generally than for the specific GaN (101̄0) surface catalyst. © 2010 American Chemical Society