Laser-induced fluorescence and microwave-optical double-resonance study of the B1Σ+-X1Σ+ system of magnesium monoxide

Doppler-limited, laser-induced fluorescence spectra on the B¹Σ⁺-X¹Σ⁺ (v′ = v″ = 0 and 1) system of MgO have been obtained. The results of the optical analysis were merged with our microwave-optical double-resonance measurements to produce the following set of spectroscopic parameters for the B and X states, where the units are in cm^?1, and the uncertainties represent 95% confidence limits: T′_0.0 = 20003.594(2); B′₀ = 0.58004(3); D′₀ = 1.13(2) × 10^?6; B″₀ = 0.57198(3); D″₀ = 1.20(2) × 10⁶; T′_1.1 = 20043.423(2); B′₁ = 0.57528(4); D′₁ = 1.14(11) × 10⁶; B″₁ = 0.56674(4); D″₁ = 1.22(10) × 10⁶.     

离子声等离子体波的动力屏蔽

本文讨论了离子声等离子体波的激发条件和它们对荷电粒子间相互作用势的动力屏蔽效应.对一些具有两个未完全被充满的外层电子能带的金属,计算了这种屏蔽效应,并研究了此动力效应对金属钯中氘-氘聚变反应率的影响.     

Measurement of the partial photoionization cross sections and asymmetry parameters of S atoms in the photon energy range 10.0-30.0 eV using constant-ionic-state spectroscopy

The partial photoionization cross sections and asymmetry parameters of S atoms have been measured using constant-ionic-state (CIS) spectroscopy in the photon energy range 10.0-30.0 eV. The ionizations investigated in these CIS experiments are the (3p)(-1) ionizations S(+)((4)S)<--S((3)P), S(+)((2)D)<--S((3)P), and S(+)((2)P)<--S((3)P). For the first time Rydberg series which converge to the fourth ionization limit have been observed and assignments of these series have been proposed. These correspond to excitations to Rydberg states that are parts of series which converge to the fourth ionization limit, S(+)((4)P)<--S((3)P) (3s)(-1), and autoionize to the lower S(+)((4)S), S(+)((2)D), or S(+)((2)P) states. For each series observed in the CIS spectra photoelectron angular distribution studies, combined with other evidence, has allowed the angular momentum character of the free electron on autoionization to be determined.     

Ab initio calculations on SnCl2 and Franck-Condon factor simulations of its ã-X and B-X absorption and single-vibronic-level emission spectra

Minimum-energy geometries, harmonic vibrational frequencies, and relative electronic energies of some low-lying singlet and triplet electronic states of stannous dichloride, SnCl(2), have been computed employing the complete-active-space self-consistent-field/multireference configuration interaction (CASSCF/MRCI) and/or restricted-spin coupled-cluster single-double plus perturbative triple excitations [RCCSD(T)] methods. The small core relativistic effective core potential, ECP28MDF, was used for Sn in these calculations, together with valence basis sets of up to augmented correlation-consistent polarized-valence quintuple-zeta (aug-cc-pV5Z) quality. Effects of outer core electron correlation on computed geometrical parameters have been investigated, and contributions of off-diagonal spin-orbit interaction to relative electronic energies have been calculated. In addition, RCCSD(T) or CASSCF/MRCI potential energy functions of the X(1)A(1), ?(3)B(1), and B(1)B(1) states of SnCl(2) have been computed and used to calculate anharmonic vibrational wave functions of these three electronic states. Franck-Condon factors between the X (1)A(1) state, and the ? (3)B(1) and B (1)B(1) states of SnCl(2), which include anharmonicity and Duschinsky rotation, were then computed, and used to simulate the ?-X and B-X absorption and corresponding single-vibronic-level emission spectra of SnCl(2) which are yet to be recorded. It is anticipated that these simulated spectra will assist spectroscopic identification of gaseous SnCl(2) in the laboratory and/or will be valuable in in situ monitoring of SnCl(2) in the chemical vapor deposition of SnO(2) thin films in the semiconductor gas sensor industry by laser induced fluorescence and/or ultraviolet absorption spectroscopy, when a chloride-containing tin compound, such as tin dichloride or dimethyldichlorotin, is used as the tin precursor.     

Franck-Condon simulation of the photoelectron spectrum of AsCl₂ and the photodetachment spectrum of AsCl ₂⁻ employing UCCSD(T)-F12a potential energy functions: IE and EA of AsCl₂

The currently most reliable theoretical estimates of the adiabatic ionization energies (AIE₀) from the X?²B₁ state of AsCl₂ to the X?¹A₁ and ã³B₁ states of AsCl, and the electron affinity (EA₀) of AsCl₂, including ΔZPE corrections, are calculated as 8.687(11), 11.320(23), and 1.845(12) eV, respectively (estimated uncertainties based on basis‐set effects at the RCCSD(T) level). State‐of‐the‐art ab initio calculations, which include RCCSD(T), CASSCF/MRCI, and explicitly correlated RHF/UCCSD(T)‐F12x (x = a or b) calculations with basis sets of up to quintuple‐zeta quality, have been carried out on the X?²B₁ state of AsCl₂, the X?¹A₁, ã³B₁, and ùB₁ states of AsCl, and the X?¹A₁ state of AsCl. Relativistic, core correlation and complete basis‐set (CBS) effects have been considered. In addition, computed UCCSD(T)‐F12a potential energy functions of relevant electronic states of AsCl₂, AsCl, and AsCl were used to calculate Franck–Condon factors, which were then used to simulate the valence photoelectron spectrum of AsCl₂ and the photodetachment spectrum of AsCl, both yet to be recorded. Lastly, we have also computed the AIE and EA values for NCl₂, PCl₂, and AsCl₂ at the G4 level and for SbCl₂ at the RCCSD(T)/CBS level. The trends in the AIE and EA values of the group V pnictogen dichlorides, PnCl₂, where Pn = N, P, As, and Sb, were examined. The AIE and EA of PCl₂ were found to be smaller than those of AsCl₂, contrary to the order expected from the IE values of P and As. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011     

A study of the atmospherically important reactions of dimethylsulfide (DMS) with I2 and ICl using infrared matrix isolation spectroscopy and electronic structure calculations

The reactions of dimethylsulfide (DMS) with molecular iodine (I(2)) and iodine monochloride (ICl) have been studied by infrared matrix isolation spectroscopy by co-condensation of the reagents in an inert gas matrix. Molecular adducts of DMS + I(2) and DMS + ICl have also been prepared using standard synthetic methods. The vapour above each of these adducts trapped in an inert gas matrix gave the same infrared spectrum as that recorded for the corresponding co-condensation reaction. In each case, the infrared spectrum has been interpreted in terms of a van der Waals adduct, DMS?:?I(2) and DMS?:?ICl, with the aid of infrared spectra computed for their minimum energy structures at the MP2 level. Computed relative energies of minima and transition states on the potential energy surfaces of these reactions were used to understand why they do not proceed further than the reactant complexes DMS?:?I(2) and DMS?:?ICl. The main findings of this research are compared with results obtained earlier for the DMS + Cl(2) and DMS + Br(2) reactions, and the atmospheric implications of the conclusions are also considered.     

算术级数中的陈景润定理 *

设N为一充分大的偶数且q≥ 1 ,(l_i,q) =1 (i=1 ,2 ) ,l₁+l₂ ≡N(modq) .证明了方程N =p+P₂ ,p≡l1(modq) ,P₂ ≡l₂ (modq)对区间 1 ,N^1/37中除了ON^1/37log^-5 N个例外的整数q ,都有无穷多解 ,其中p是素数 ,P₂ 为一至多有2个素因子的殆素数 .     

“下愚”最智 “上智”最愚

历代反动派总是宣扬孔老二“上智与下愚不移”的唯心论说教,把它作为“剥削有理”、“压迫有理”的根据。林彪这个地主资产阶级的代理人,为了篡党夺权,复辟资本主义,建立林家法西斯王朝,也鼓吹“上智下愚”的谬论。他把自己吹成“生而知之”的“天才”,以“至贵”、超人自居,污蔑劳动人民“愚昧”、“落后”,只会说“恭喜发财”,只能想“油盐酱醋柴”。     

New isoquinolines as potential bronchodilator agents

The syntheses of 5-hydroxy-6-hydroxymethyl, 6-hydroxy-7-hydroxymethyl and 7-hydroxy-6-hydroxymethyl-1-(3,4,5-trimethoxybenzyl)-1,2,3,4-tetrahydroisoquinolines (1d), (1b) and (1c) respectively, are described.