干涉现象中能量叠加的实验研究

经典的波动理论与量子理论均分别对杨氏双缝干涉实验进行了解释。由于两个解释理论一个简单直观、一个复杂抽象,但两者结果一致,使得学生在学习中容易接受波动理论而排斥量子理论。文中通过实验观测了杨氏双缝干涉光场中能量传递与叠加的实际情况,结果显示实验实际情况与波动理论解释明显不相符合,而与量子理论解释完全相符。通过实验,使学生直观地看到波动理论的局限性,并加深学生对量子力学相关理论的理解。     

A new approach to counterpoise correction to BSSE

In the present work the intermolecular BSSE, associated to the A-B interaction, is obtained by subtracting the intramolecular BSSE of the fragments from the intramolecular BSSE of the supermolecule, and considering every atom as a fragment in the calculation of each intramolecular BSSE. This atom by atom scheme (CP(aa)) is based on the consideration that the proximity of the fragments may affect the intramolecular BSSE of every involved species, and artificially influences the value of the BSSE associated to the supermolecule formation. It drastically decreases the reported counterpoise overcorrection of the A-B interaction, even though it does not deal with all the overcorrection because it includes all the orbitals, and not only the unoccupied ones. This new approach has been tested on the water dimer, some hydrogen fluoride weakly bonded complexes, the conformational analysis of 1,2-dichloroethane, and the reaction profile of formaldehyde + OH reaction.     

The conformers of phenylglycine

The neutral form of the unnatural amino acid phenylglycine was vaporized by laser ablation, and the presence of two conformers was detected in a supersonic expansion by Fourier transform microwave spectroscopy. Both conformers were unequivocally identified by comparison of their experimental rotational and quadrupole coupling constants with those calculated ab initio. The most stable conformer is stabilized by intramolecular hydrogen bonds N-H...O=C, N-H...pi (with the closest C-C bond in the aromatic ring), and a cis-COOH interaction. The other conformer exhibits a O-H...N hydrogen bond between the hydrogen atom of the hydroxyl group and the lone pair at the nitrogen atom.     

INVERSE SCATTERING PROBLEMS BY SINGULAR SOURCE METHODS

The inverse scattering problems are to detect the property of obstacles from the measurements outside the obstacles. One of important research areas in this topic is the recovery of boundary property for impenetrable obstacles. In this paper, we would like to give a brief review about the recently developed singular source methods. There are three different methods in this category, namely, linear sampling method, pointsource method and probe method. We also present some recent new results about the probe method.     

Shapes and Internal Dynamics of the 1:1 Adducts of Ammonia with trans and gauche Ethanol: A Rotational Study

Two 1:1 adducts of ammonia with ethanol have been characterized by using pulsed‐jet FT microwave spectroscopy. They are formed with two different (trans and gauche), stable conformers of ethanol. Several internal‐dynamics effects are reflected in the features of the rotational spectra. The trans complex shows the tunneling effects owing to internal rotation of both ammonia and the methyl group. The rotational transitions of the gauche species exhibit a small splitting that is related to tunneling through the potential‐energy barrier between the two equivalent minima.     

Density Functional Theory Study of the Interaction between Thymine and Luteolin

The density function B3LYP method has been used to optimize the geometries of the luteolin, thymine and luteolin‐thymine complexes at 6‐31+G?? basis. The vibrational frequencies have been studied at the same level to analyze these seventeen complexes, respectively. Theories of atoms in molecules (AIM) and natural bond orbital (NBO) have been utilized to investigate the hydrogen bonds involved in all the systems. The interaction energies of the complexes corrected by basis set superposition error are between ?93.00–?76.69 kJ/mol. The calculating results indicate that strong hydrogen bonding interactions have been found in the luteolin‐thymine complexes.     

The rotational spectrum of 13C2HD in the ground and excited bending states

The pure rotational spectrum of ¹³C₂HD was recorded in the range 100–700 GHz. Lines belonging to the ground vibrational state were observed from J^″ = 1 to J^″ = 11. Several absorption lines were also detected in the bending states v₄ = 1 (Π), v₅ = 1 (Π), v₄ = 2 (Σ⁺ and Δ), v₅ = 2 (Σ⁺ and Δ), v₄ = v₅ = 1 (Σ^?, Σ⁺ and Δ), v₄ = 3 (Π and Φ) and v₅ = 3 (Π and Φ). The transition frequencies measured in this work were fitted together with all the infrared lines available in the literature. The global fit allowed a very accurate determination of the vibrational, rotational and ?-type interaction parameters for the bending states of this molecule.     

结构化学小班讨论介绍——态叠加原理

简要介绍了结构小班讨论课中关于主题文献"态叠加原理"的讨论情况及讨论过程中需要注意的问题。     

ESR study of molecular orientation and dynamics of TEMPO derivatives in CLPOT 1D nanochannels

The molecular orientations and dynamics of 2,2,6,6‐tetramethyl‐1‐piperidinyloxyl (TEMPO) radical derivatives with large substituent groups at the 4‐position (4‐X‐TEMPO) in the organic one‐dimensional nanochannels within the nanosized molecular template 2,4,6‐tris(4‐chlorophenoxy)‐1,3,5‐triazine (CLPOT) were examined using ESR. The concentrations of guest radicals, including 4‐methoxy‐TEMPO (MeO‐TEMPO) or 4‐oxo‐TEMPO (TEMPONE), in the CLPOT nanochannels in each inclusion compound (IC) were reduced by co‐including 4‐substituted‐2,2,6,6‐tetramethylpiperidine (4‐R‐TEMP) compounds at a ratio of 1 : 30–1 : 600. At higher temperatures, the guest radicals in each IC underwent anisotropic rotational diffusion in the CLPOT nanochannels. The rotational diffusion activation energy, E_a, associated with MeO‐TEMPO or TEMPONE in the CLPOT nanochannels (6–7 kJ mol^?1), was independent of the size and type of substituent group and was similar to the E_a values obtained for TEMPO and 4‐ hydroxy‐TEMPO (TEMPOL) in our previous study. However, in the case in which TEMP was used as a guest compound for dilution (spacer), the tilt of the rotational axis to the principal axis system of the g ‐tensor, and the rotational diffusion correlation time, τ_R, of each guest radical in the CLPOT nanochannels were different from the case with other 4‐R‐TEMP. These results indicate the possibility of controlling molecular orientation and dynamics of guest radicals in CLPOT ICs through the appropriate choice of spacer. Copyright © 2016 John Wiley & Sons, Ltd.