Alkali-earth atoms have a long-lived electronic excited state, and when atoms in this excited state are localized in the Fermi sea of ground state atoms by an external potential, they serve as magnetic impurities, due to the spin-exchange interaction between the excited and the ground state atoms. This can give rise to the Kondo effect. However, in order to achieve this effect in current atomic gas experiment, it requires the Kondo temperature to be increased to a sizable portion of the Fermi temperature. In this paper we calculate the confinement-induced resonance (CIR) for spin-exchanging interaction between the ground and the excited states of the alkali-earth atoms, and we propose that the spin-exchange interaction can be strongly enhanced by utilizing the CIR. We analyze this system by the renormalization group approach, and we show that nearby a CIR, the Kondo temperature can be significantly enhanced. * Electronic address: pengzhang@ruc.edu.cn † Electronic address: hzhai@tsinghua.edu.cn arXiv:1509.01350v3 [cond-mat.quant-gas]

Herein,viathe first-principles density functional theory, CASTEP code, we investigated the 15 vibrational normal modes of ferroelectric hydrogen-ordered phase of ice Ic and the two peaks of hydrogen bond are clarified.

For liquid water in the far-infrared spectrum, phonons of molecular vibrations constitute two bands with a narrow gap at around 30 meV. Interestingly, there are two distinct peaks for ice in this gap. We demonstrated that the two peaks come from two kinds of translational modes. Considering different O–O–O bending constants, we yielded two frequencies based on the ideal model of ice Ic. These two kinds of vibrational modes do not exist in liquid water due to the collapse of the rigid tetrahedral structure. Thus, a window remains for ice resonance absorption with minimum energy loss in liquid water. A new method to decompose gas hydrates was proposed by supplying two terahertz radiation energies at ∼6.8 and 9.1 THz. This is also applicable to flow assurance in gas pipelines, aircraft deicers, and so on. Experimental measurements are expected to verify this finding along with the rapid development of a THz laser.

Despite its simple molecular structure, water is still a mystery to scientists. For the atomic and molecular vibrational modes of ice, as is well known, there are two kinds of vibrations: intra-molecular O—H stretching vibration and H—O—H bending vibration within the molecules and three kinds of molecular spatial rotations. However, thirty years ago, a high flux inelastic neutron scattering experiment showed that there are two distinct characteristic peaks in the far-infrared molecular translational vibration region of many ice phases. The origins of these peaks have not been determined till now. In this work, based on the CASTEP code, a first-principles density functional theory plane wave programme, the vibrational spectra as well as the vibrational normal modes of a series of ice phases are investigated. Two kinds of intrinsic hydrogen bond vibrational modes are first found in hydrogen-ordered ice Ic. Then it is found to be a general rule among ice family. Based on the ideal model, we prove that the two vibrational modes can be classified as four-bond vibration and two-bond vibration. There are many coupling modes in-between due to tetrahedral structure deformation under high pressure. Besides, there are also some optical vibrational modes with lower energy in the translational region, such as cluster vibrations and inter-plane vibrations. In Ice VII/VIII and XV/VI, each of which consists of two sublattices, there exist non-hydrogen bond vibrations. These molecular translational vibrations can explain all the far-infrared vibrational spectrum of ice phase, which makes up the last piece of the jigsaw puzzle for the molecular vibration theory of ice. The two vibrational modes do not exist in liquid water due to the collapse of the rigid tetrahedral structure. Thus, a window remains for ice resonance absorption with minimum energy loss in water. This theory is expected to be applicable to industrial deicing, food thawing, gas hydrate mining, and biomolecule frozen molding, etc.