MRCI及其近似方法下C2分子X1∑+g, B1△g和B'1∑+g态的势能曲线

运用MRCI及其近似方法计算得到C2分子X1∑+g,B1△+g,和B'1∑+g 3个电子态的势能曲线,并以FCI方法为基准,考察比较各种方法的优缺点.MRCI计算与FCI计算几乎不存在差别,在FCI计算不现实的情况下,MRCI计算足以作为基准考验其他计算方法.多种近似方法均能达到化学精度,并提出一个有效的选择参考组态的方法,提高MRCI计算效率的同时,保证计算的精确性.     

Potential energy curves for the X1∑ g, B1△g and B''''1∑ g states of C2 using MRCI and approximate CI methods

The potential energy curves for the X1∑ g, B1△g and B′1∑ g states of C2 have been studied by using MRCI and approximate CI methods, and are benchmarked against the calculations of full configuration interaction (FCI). The results obtained by MRCI method agree with the FCI very well, and even are accurate enough to compare other approximate methods as benchmark, when the calculations of FCI are not feasible. The approximate CI methods mentioned in this paper are reliable for treating chemical problems.     

Analysis of the vibronic structure of the 1A1g → 1B3g, 1B2u transition in biphenyl -h10 and -d10

The absorption spectra of biphenyl-h₁₀ and -d₁₀ crystals in the region of the ¹A_1g → 1B_3g, ¹B_2u transitions are interpreted in terms of vibronic coupling of the two closely spaced electronic states by six b_1u vibrations.     

Temperature dependence of the relaxation rate constants of the a 1Δg and b 1Σ +g states of oxygen isotopes

The relaxation rate constants of the low-lying electronic singlet states, a ¹Δ_g and b ¹Σ⁺_g , of gaseous natural O₂ and of the isotope ¹⁸O₂ were investigated as a function of temperature from 100 to 295 K. The measured increase of the rate constants with temperature is in good agreement with a theory of electronic-to-vibrational-translational energy transfer. The significant effects of the different electronic states and of the isotope masses on the absolute values of the relaxation rate constants, which range from 1.0× 10⁻²⁰ to 3.9× 10⁻¹⁷ s⁻¹ molecule⁻¹ cm³ at 295 K, are discussed.     

烯烃与~1△g态~1O_2的氧化反应

本文系统研究，综述有机物光氧化反应基础理论之一的烯烃与第一激发单重态氧分子（￣１△ｇ态￣１Ｏ＿２）的氧化反应，其中包括共轭双烯与￣１△ｇ态￣１Ｏ＿２的氧化反应、单烯烃与￣１－△ｇ态￣１Ｏ＿２的氧化反应及烯（ｅｎｅ）反应，分别介绍它们的典型反应、反应特性、反应机理及其在有机合成上的应用。     

Excited-state dynamics of trans,trans-1,3,5,7-octatetraene: estimation of decay rate constants of 1(1)B(u) ⇝ 2(1)A(g) and 2(1)A(g) ⇝ 1(1)A(g) internal conversions

The general expressions we previously derived for calculating internal conversion rate constants between two adiabatic displaced-distorted-rotated potential energy surfaces, by including all vibratinal modes, are applied to estimate the decay rate constants of 1(1)B(u) ? 2(1)A(g) and 2(1)A(g) ? 1(1)A(g) internal conversions in trans,trans-1,3,5,7-octatetraene molecule. The minimal models with respect to the number and types of vibrational modes are determined for these processes. Our calculations show that in the low temperature limit the 1(1)B(u) ? 2(1)A(g) internal conversion takes place on a 232-290 fs time scale in the condensed phase and 2 ps in the gas phase, whereas 2(1)A(g) ? 1(1)A(g) internal conversion takes place on a 2 μs time scale under the isolated conditions.     

Bi和O2(1△g)的化学发光研究

The emission spectra of BiO has been first obtained by studying the reaction: Bi+O_2(~1△_g)in the atomic-beam apparatus. 22 new bands has been obtained from the emission spectra of BiO (A ~2Π_g) which are attributed to the collisional energy transfer process of BiO(X,v)+O_2(b ~1Σ_g~+). The O_2(b ~1Σ_g~+) is produced by the following process: O_2(~1△_g)+O_2(~1△_g)→O_2(b ~1Σ_g~+)+O_2(X ~3Σ_g~-).     

Photodissociation of CS2+( 2 Πg) via (1+1) Excitation

Photodissociation dynamics of CS2+molecular ions has been investigated by (1+two-photon resonance technique. CS2+were prepared by (3+1) resonance-enhanced multi-photon ionization (REMPI) of CS2molecules at 483. 2nm. The photofragment S+excitati (PHOFEX) spectra were recorded by scanning another laser in the 424~482nm region, and we assigned essentially to CS2+(~A2Πu,3/2(v′=0~4)←~X2Πg,3/2(0,0,0)) and (~A2Πu,1/2(v′=0,4)←~X2Πg,1/2(0,0,0)) (herev′=v1′+(1/2)v2′) transitions. The S+production channel wpreliminarily attributed to, (i) one-photon excitation CS2+from the ground state~X2Πgto texcited state~A2Πu; (ii) vibronic coupling between the~A2Πustate and the high vibrational lev in the~X2Πgstate; (iii) second photon excitation from the coupling vibrational levels to the excied state~B2Σu+and dissociation to produce S++ CS via the repulsive4Σ-state through spin-orb interaction between the~B2Σu+and4Σ-states.     

CS2 +( 2 Πg )的(1+1)光解离动力学研究

在气束条件下,利用483.2 nm的激光(3+1)共振增强多光子电离(REMPI)CS2分子以产生CS2+离子源,用另一束可调谐激光在424～482 nm内,通过对CS2+( 2 Πg)(1+1)双光子共振解离产生的碎片离子激发谱的探测,来获取CS2+ 的光解离动力学信息.光解离碎片S+的激发谱 (PHOFEX)可归属为CS2+ ( 2 Πu,3/2 (v′=0～4, v′=v1′+ (1/2)v2′) ← 2 Πg,3/2 (0,0,0))和 ( 2 Πu,1/2(v′=0～4)← 2 Πg,1/2(0,0,0))的跃迁.对CS2+光解离动力学的研究表明,其产生S+的通道为:(i)CS2+吸收一个光子从基态 2 Πg共振激发至 2 Πu态,(ii)已布居的 2 Πu态的振动能级和 2 Πg态的高振动能级产生耦合, (iii)吸收第二个光子从上述耦合的振动能级进一步激发至 2 Σu +态,再通过 2 Σu +态与4Σ- 态间的自旋-轨道相互作用,经由4Σ- 排斥态解离产生S++CS.     

Bi和O_2(~1△g)的化学发光研究

本文首次报导了Bi和O_2(~1△g)反应的化学发光光谱。依据能量守恒,从碰撞传能的角度探讨了化学发光机理。实验结果和讨论     

The 1(5)Π(g) state of C2

We report ab initio spectroscopic constants for the recently identified 1(5)Π(g) state of C(2) [P. Bornhauser, Y. Sych, G. Knopp, T. Gerber, and P. P. Radi, J. Chem. Phys. 134, 044302 (2011)]. The calculations are performed at the multi-reference configuration interaction level of theory with Davidson's correction using aug-cc-pV6Z basis sets and include core-valence correlation and relativistic corrections obtained with quadruple-zeta bases. Such treatment accurately reproduces the experimentally observed constants of the a(3)Π(u) and other states. Thus, we expect our calculated ω(e) value for the 1(5)Π(g) state to be within a few cm(-1), and rotational constants to be within 0.1% of experiment. Agreement with available spectroscopic data is excellent, with the calculations strongly suggesting that the 1(5)Π(g) vibrational level observed by Bornhauser et al. is v = 0.     

The (1) 3Σg+ electronic state of Cs2

Laser-induced fluorescence of Cs₂ molecules, recorded by high-resolution Fourier spectroscopy, has been used for the first spectroscopic identification of the lowest gerade triplet (1) ³Σ_g⁺ electronic state. This state can be described by the molecular parameters: T_e = 11602.10 cm⁻¹, B_c = 8.258×10⁻³ cm⁻¹, D_c = 2.56×10⁻⁹ cm⁻¹ and R_c = 5.5425 Å. Determination of the absolute vibrational numbering will require further experiments.     

Collisional relaxation of O2(X3Σg(-), υ = 1) and O2(a1Δg, υ = 1) by atmospherically relevant species

Laboratory measurements are reported of the rate coefficient for collisional removal of O(2)(X(3)Σ(g)(-), υ = 1) by O((3)P), and the rate coefficients for removal of O(2)(a(1)Δ(g), υ = 1) by O(2), CO(2), and O((3)P). A two-laser method is employed, in which the pulsed output of the first laser at 285 nm photolyzes ozone to produce oxygen atoms and O(2)(a(1)Δ(g), υ = 1), and the output of the second laser detects O(2)(a(1)Δ(g), υ = 1) via resonance-enhanced multiphoton ionization. The kinetics of O(2)(X(3)Σ(g)(-), υ = 1) + O((3)P) relaxation is inferred from the temporal evolution of O(2)(a(1)Δ(g), υ = 1), an approach enabled by the rapid collision-induced equilibration of the O(2)(X(3)Σ(g)(-), υ = 1) and O(2)(a(1)Δ(g), υ = 1) populations in the system. The measured O(2)(X(3)Σ(g)(-), υ = 1) + O((3)P) rate coefficient is (2.9 ± 0.6) × 10(-12) cm(3) s(-1) at 295 K and (3.4 ± 0.6) × 10(-12) cm(3) s(-1) at 240 K. These values are consistent with the previously reported result of (3.2 ± 1.0) × 10(-12) cm(3) s(-1), which was obtained at 315 K using a different experimental approach [K. S. Kalogerakis, R. A. Copeland, and T. G. Slanger, J. Chem. Phys. 123, 194303 (2005)]. For removal of O(2)(a(1)Δ(g), υ = 1) by O((3)P), the upper limits for the rate coefficient are 4 × 10(-13) cm(3) s(-1) at 295 K and 6 × 10(-13) cm(3) s(-1) at 240 K. The rate coefficient for removal of O(2)(a(1)Δ(g), υ = 1) by O(2) is (5.6 ± 0.6) × 10(-11) cm(3) s(-1) at 295 K and (5.9 ± 0.5) × 10(-11) cm(3) s(-1) at 240 K. The O(2)(a(1)Δ(g), υ = 1) + CO(2) rate coefficient is (1.5 ± 0.2) × 10(-14) cm(3) s(-1) at 295 K and (1.2 ± 0.1) × 10(-14) cm(3) s(-1) at 240 K. The implications of the measured rate coefficients for modeling of atmospheric emissions are discussed.     

Untersuchung g?rtnerischer Erden

Ohne Zusammenfassung     

Laser excitation spectrum of the 0g+(X 1Σg+)−0u+(3Πu) transition in Cd2

Spectroscopic constants and bond strengths of ground-state 0_g⁺(¹Σ_g⁺) and excited state 0_u⁺(³Π_u) Cd₂ van der Waals molecules have been determined by laser excitation of Cd₂ spectra in a supersonic expansion of cadmium vapor.     

传能反应O(1D)+CO2(1Σ+g)→O(3P)+CO2(1Σ+g)中间物机理的理论研究

利用ab initio 量子化学方法研究了自旋禁阻的传能反应O(1D)+CO2(1Σ+g)→O(3P)+CO2(1Σ+g)的反应机制, 通过中间化合物CO3的单、三重态的势能面交叉点的确认, 证明了中间物传能机理的可行性. 同时计算了交叉点处的自旋-轨道偶合和面间跃迁几率, 进一步证明了中间化合物CO3的形成在传能过程中的重要作用.     

High resolution spectral analysis of oxygen. I. Isotopically invariant Dunham fit for the X(3)Σ(g)(-), a(1)Δ(g), b(1)Σ(g)(+) states

We have developed a simultaneous global fit to the MW, THz, infrared, visible, and UV transitions of all six oxygen isotopologues, (16)O(16)O, (16)O(17)O, (16)O(18)O, (17)O(17)O, (17)O(18)O, (18)O(18)O, with the objective of predicting all transitions below the O((3)P) + O((3)P) dissociation threshold as well as the B(3)Σ(u) (-) state from O((3)P)+O((1)D) within state-of-the-art experimental uncertainty. Here, we report an isotopically invariant Dunham fit for the lowest three electronic states, X(3)Σ(g)(-), a(1)Δ(g), and b(1)Σ(g)(+). Experimental transition frequencies involving these three states of all six O(2) isotopologues were critically reviewed and incorporated into the analysis. For the (16)O(16)O isotopologue, experimental data sample vibrational states v = 0-31 for X(3)Σ(g)(-), v = 0-10 for a(1)Δ(g), and v = 0-12 for b(1)Σ(g)(+). To the best of our knowledge, this is the first analysis that simultaneously fits spectra from all six O(2) isotopologues.