TDDFT study on the excited‐state hydrogen bonding of N‐(2‐hydroxyethyl)‐1,8‐naphthalimide and N‐(3‐hydroxyethyl)‐1,8‐naphthalimide in methanol solution

The time‐dependent density functional theory method was performed to investigate the excited‐state hydrogen‐bonding dynamics of N‐(2‐hydroxyethyl)‐1,8‐naphthalimide (2a) and N‐(3‐hydroxyethyl)‐1,8‐naphthalimide (3a) in methanol (meoh) solution. The ground and excited‐state geometry optimizations, electronic excitation energies, and corresponding oscillation strengths of the low‐lying electronically excited states for the complexes 2a + 2meoh and 3a + 2meoh as well as their monomers 2a and 3a were calculated by density functional theory and time‐dependent density functional theory methods, respectively. We demonstrated that the three intermolecular hydrogen bonds of 2a + 2meoh and 3a + 2meoh are strengthened after excitation to the S₁ state, and thus induce electronic spectral redshift. Moreover, the electronic excitation energies of the hydrogen‐bonded complexes in S₁ state are correspondingly decreased compared with those of their corresponding monomer 2a and 3a. In addition, the intramolecular charge transfer of the S₁ state for complexes 2a + 2meoh and 3a + 2meoh were theoretically investigated by analysis of molecular orbital. Copyright © 2014 John Wiley & Sons, Ltd.     

Extensive spectroscopic calculations on 12 low-lying electronic states of AlN molecule including transition properties

Using the CASSCF method followed by the internally contracted MRCI approach in combination with the correlation-consistent basis sets, the potential energy curves (PECs) are calculated for the X³Π, A³Σ^-, B³Σ⁺, C³Π, E³Δ, a¹Σ⁺, b¹Π, c¹Δ, d¹Σ⁺, e¹Π, 2³Σ^? and 3³Σ^? electronic states of AlN molecule for internuclear separations from 0.1 to 1.0 nm. All the electronic states correlate to the three dissociation channels, Al(²P_u) + N(⁴S_u), Al(²P_u) + N(²D_u) and Al(²P_u) + N(²P_u). Of these 12 electronic states, only the 2³Σ^? possesses the double well. The PECs determined by the internally contracted MRCI approach are corrected for size-extensivity errors by means of the Davidson correction. The convergent behavior of present calculations is observed with respect to the basis set and level of theory. The effect of core-valence correlation and scalar relativistic corrections on the spectroscopic parameters is discussed. Scalar relativistic correction calculations are performed by the third-order Douglas-Kroll Hamiltonian approximation at the level of cc-pVTZ basis set. Core-valence correlation corrections are included with a cc-pCVTZ basis set. All the PECs are extrapolated to the complete basis set limit. The spectroscopic parameters are evaluated by fitting the first ten vibrational levels when available, which are obtained by solving the ro-vibrational Schrödinger equation with the Numerov’s method. The spectroscopic parameters are compared with those reported in the literature. Excellent agreement is found between the present results and the measurements. Analyses show that the spectroscopic parameters reported in this paper can be expected to be reliably predicted ones. The Franck-Condon factors and radiative lifetimes of the transitions from the A³Σ^?, B³Σ⁺, C³Π, a¹Σ⁺ and b¹Π electronic states to the ground state are calculated for several low vibrational levels, and some necessary discussion has been made.     

Quantum confinement in graphene quantum dots

By performing density functional theory calculations, we studied the quantum confinement in charged graphene quantum dots (GQDs), which is found to be clearly edge and shape dependent. It is found that the excess charges have a large distribution at the edges of the GQD. The resulting energy spectrum shift is very nonuniform and hence the Coulomb diamonds in the charge stability diagram vary irregularly, in good agreement with the observed nonperiodic Coulomb blockade oscillation. We also illustrate that the level statistics of the GQDs can be described by a Gaussian distribution, as predicted for chaotic Dirac billiards.

     

凝胶渗透色谱-气相色谱质谱法测定：花生中6种除草剂农药残留

建立了凝胶渗透色谱一气相色谱质谱（GPC～GC=MS）法测定花生中6种除草剂（氟乐灵、异恶草酮、甲草胺、二甲戊乐灵、乙氧氟草醚、喹禾灵）农药残留的方法。样品经乙腈提取,氨基固相萃取柱和凝胶渗透色谱净化,在选择离子扫描（SIM）模式下进行气相色谱质谱法测定,外标法定量。6种除草剂浓度在0．02-1．00mg／L范围内与色谱峰面积呈良好的线性,线性相关系数为O．9949～0．9998,添加回收率为77．8％-101．6％,测定结果的相对标准偏差为4．4％～11．4％（月=5）,方法的检出限为0．1～1．3μg／kg。     

Rotational and rovibrational transitions in the a 1Δ2 and b 1Σ+0+ states of sulfur monoxide radical

ABSTRACT

Sulfur monoxide radical has widely been detected in outer space using ground-state spectroscopy. The a ¹Δ₂ and b ¹Σ⁺₀₊ states of this radical have low excitation energies, and they possibly exist in outer space. In this work, the potential energy curves and dipole moment functions of the two states were evaluated using the complete active space self- consistent field method, followed by the valence internally contracted multireference configuration interaction approach. The transition line positions, oscillator strengths, band transition dipole matrix elements, Einstein A coefficients, and Franck–Condon factors of all transitions were calculated for lower vibrational levels at rotational angular momentum quantum number J up to 150. The transition line positions calculated in this study are in good agreement with the experimental results. The rovibrational transition became noticeably weak at Δυ > 5. Comparing the results of a ¹Δ₂ and b ¹Σ⁺₀₊ states reported in this paper with the previous values, we conclude that these results are the most accurate and complete to date.     

Transition probabilities of the X1Σ+, A1Π, B1Δ, C1Σ+, and D1Π states of the AlO+ cation

ABSTRACT

This study computes the potential energy curves of the X¹Σ⁺, A¹Π, B¹Δ, C¹Σ⁺, and D¹Π states of AlO⁺ cation and the transition dipole moments between them. The orders of the rotationless radiative lifetimes are 10–100?μs for the A¹Π state, 1–1000?ms for the B¹Δ state, 10?ns for the first well and 100?ns for the second well of the C¹Σ⁺ state, and 1?μs for the D¹Π state. Emissions of the B¹Δ–A¹Π and D¹Π–C¹Σ⁺ systems are so weak that they are hardly measured via spectroscopy, the emissions of the C¹Σ⁺–X¹Σ⁺, C¹Σ⁺–A¹Π, and D¹Π–X¹Σ⁺ systems are so strong that they can be detected readily, and emissions of the A¹Π–X¹Σ⁺ and D¹Π–A¹Π systems can be observed through spectroscopy only by a significant effort. There is a strong great similarity between spontaneous emissions of the A¹Π–X¹Σ⁺ system of the AlO⁺ cation and the A²Π–X²Σ⁺ system of the AlO radical. The emissions of the A²Π–X²Σ⁺ system of the AlO radical have been measured in outer space Therefore, it is highly possible that the emissions of the A¹Π–X¹Σ⁺ system of the AlO⁺ cation can be detected in the astrophysical media.     

A new asymmetric anthracene derivative with high mobility

An asymmetric anthracene derivative(4-HDPA) was designed and synthesized. With the optimization of proper scenario of fabrication process, top-contact thin film devices based on 4-HDPA exhibit mobility as high as 3.59 cm~2 V~(–1) s~(–1), while its singlecrystal devices exhibit mobility as high as 5.12 cm~2 V~(–1) s~(–1), which is higher than the symmetrical counterpart of 4-HDPA in both single-crystal and thin film devices.     

TOTAL CROSSS ECTIONS FOR ELECTRON SCATTERING FROM SIMPLE HYDROCARBON MOLECULES: C_2H_4,C_2H_6 AND C_3H_8

１ＩＮＴＲＯＤＵＣＴＩＯＮＳｉｍｐｌｅｈｙｄｒｏｃａｒｂｏｎｍｏｌｅｃｕｌｅｓａｓａｎｉｍｐｏｒｔａｎｔｃｏｍｐｏｎｅｎｔｉｎｔｈｅｐｌａｎｅｔａｒｙａｎｄｃｏｍｅｔａｒｙａｔｍｏｓｐｈｅｒｅａｎｄａｓａｄｏｍｉｎａｎｔｍａｔｅｒｉａｌｉｎｔｈｅｆｉ...