高温下CO分子的振转跃迁光谱

采用近似方法计算了CO分子的总配分函数;利用该分子的偶极矩函数和在Morse近似下的波函数,计算了分子的振转跃迁矩阵元及在常温和高温下的吸收系数。计算结果表明,在常温(296 K)和高温下(3 000 K),计算结果与HITRAN数据库和文献值符合的很好,表明对分子总配分函数和振转跃迁矩阵元的计算是可靠的。并首次计算了CO分子在更高温度(4 000和6 000 K)下的吸收系数。     

分子振转光谱的计算机辅助标识

介绍一种计算机辅助分子光谱振转标识的交互式软件,它的主要功能是根据二次逐差原理自动将谱线分组,挑取各个支带；然后用图解的方式,以谱线频率和强度为坐标轴,将选取的各组谱线按不同的颜色或线形绘成柱状图,清晰地显示出隐藏在复杂分子光谱中的振转结构；而且,同时可以作出Loomis-Wood图辅助光谱振转标识。将本软件应用到由三氯化磷和氦气放电生成的包含多种分子的复杂光谱中,取得了满意的结果,有效地辅助了光谱的振转分析。该软件适用于对称陀螺分子和轻微不对称陀螺分子和线形分子的光谱分析。     

基于分子转-振光谱精细结构的火焰温度遥测方法

燃烧火焰温度是固体推进剂等重要参数,本文研究了基于分子转-振光谱精细结构的火焰温度遥测方法.根据分子转-振光谱线的展宽机制,研究了分子谱线线型.结合朗伯-比耳吸收定律,去除谱线中心受大气低温气体吸收影响较大的数据点后,利用谱线两翼的数据点进行谱线线型拟合,利用分子转-振光谱精细结构温度遥测方法将经拟合修正后数据反演火焰...     

磁场中HD分子振转跃迁的超精细结构

HD分子红外跃迁的精密测量被用以检验量子电动力学、确定质子-电子质量比等.但HD分子的超精细结构分裂对于测量精度是一个很重要的限制因素,并可能是实验中测得υ=2—0谱带跃迁呈特殊线型的原因之一.本文分别在耦合表象和非耦合表象下计算了HD分子振转跃迁的超精细结构,并计算了不同外加磁场下HD分子(2-0)带中R(0),P(...     

用代数方法精确研究HF分子B1Σ的振转能谱

基于代数方法(algebmic methok)可以获得双原子分子的包含最高振动能级在内的所有高阶振动能级的精确数值这一事实,又提出了一种新的代数方法(algebraic method 2)来精确研究双原子分子电子态的振转能谱和转动常数.以HF分子的B1Σ电子态为例,应用akebraic method 2方法研究了该电子态的振动量子数从v=O到v=10的所有振转能谱,获得了与实验值符合得非常好的理论结果.     

CO分子振转光谱的理论研究

采用从头算的多参考组态相互作用(MRCI)方法并结合基组aug-cc-pCVQZ计算了CO分子基态(X1Σ+)的势能曲线和偶极矩曲线,得到的势能曲线、偶极矩曲线分别与RKR势、文献的偶极矩曲线吻合较好。利用所得的势能,求解双原子分子核运动的Schrdinger方程找到了CO分子X1Σ+态转动量子数J=0时的70个振动态,对于每一振动态,分别计算了其振动能级G(v)、转动惯性常数B_v和离心畸变常数D_v,并把计算结果与已知的42个实验值做了详细比较,结果表明,计算的振动能级G(v)、转动惯性常数B_v、离心畸变常数D_v与实验值符合较好。利用G(v),B_v导出的光谱常数[谐振频率ω_e(2 160.1 cm-1)、非谐振频率ω_eχ_e(13.1 cm-1)、转动常数B_e(1.918 cm-1)、振转耦合常数α_e(0.017 3 cm-1)]也与实验值的光谱常数[ω_e(2 169.8 cm-1),ω_eχ_e(13.3 cm-1),B_e(1.931 cm-1),α_e(0.017 5 cm-1)]较为符合,这在一定程度上证明了方法MRCI/Aug-cc-pCVQZ对CO分子基态性质的计算是合适而可靠的。利用乘积近似方法计算了CO分子在常温、中温、高温时的配分函数,在此基础上,计算了CO分子在T=296 K时的1-0跃迁带的谱线强度,通过比较发现,计算所得的线强度与HITRAN数据库符合较好。进一步计算的CO分子X1Σ+态1-0,2-0,3-0,4-0,2-1,3-1和4-1跃迁带的带强度也与实验值较为吻合,同时首次计算了CO分子X1Σ+态3-2跃迁带、4-2跃迁带的线强度及带强度。     

SO分子最低两个电子态振—转谱的显关联多参考组态相互作用计算

采用显关联多参考组态相互作用(explicitly correlated multi-reference configuration interaction method,MRCI-F12)方法和相关一致基组cc-p CVQZ-F12计算了双原子分子SO的基态X~3Σ~-和第一激发态a~1?的势能曲线,研究中考虑了Davidson修正,芯-价电子关联修正和标量相对论效应.通过对这两个束缚电子态势能曲线的拟合,给出了光谱常数并与其他理论和实验结果做了比较.进一步地,获得了这两个态的振-转能级信息.本文计算结果与实验的相对误差仅在千分之一量级,对将来的实验有重要的参考价值;同时也表明MRCI-F12方法可推广到小分子体系势能面的高效、精确计算研究中.     

超冷铷铯极性分子振转光谱的实验研究

利用激光冷却俘获技术在双暗磁光阱中获得高密度的超冷铷原子和铯原子,通过光缔合方法制备超冷铷铯极性分子.采用共振增强双光子电离技术探测基三重态a³∑⁺的铷铯分子,产率约为10⁴/s.通过改变缔合光频率,获得（2）0⁺,（3）0^-,（2）0^-等分子态的高分辨振转光谱,拟合得到相应的转动常数分别为0.00349 cm^-1,0.00649 cm^-1,0.00372 cm^-1.     

氦同位素与氢分子碰撞的振转激发分波截面研究

用密耦近似方法和Tang-Toennies势模型计算了E=0·7eV时,氦原子的四种同位素3He,4He,9He,10He与氢分子H2碰撞体系的振转激发分波截面.通过分析各碰撞体系分波截面的差异,探讨了He(3He,4He,9He,10He)-H2碰撞体系的弹性碰撞、纯转动激发和振转激发情况下,其分波截面随量子数和体系约化质量的变化规律.     

氮分子A3Σu+、B3Пg、C3Пu电子态的高温高振转光谱研究

采用态平均（CASSCF）/高度相关多参考组（MRCI）方法,对N2分子A3Σu+、B3Пg、C3Пu电子态的势能、跃迁偶极矩进行了高度相关的精确计算．计算的势能在平衡位置附近与RKR拟合的势能曲线非常一致,获得的跃迁偶极矩与已有实验值符合很好。首次对A3Σu+、B3Пg、C3Пu电子态的振转光谱常数随振动量子数v的变化进行系统定量计算,其结果与已有的实验观测数据相符．同时,获得了N2分子第一正带系的0-1、0-2、1-0、1-2、1-3、2-0、2-1、2-3、3-0、3-1和3-2光谱带分别在300,3000,6000,10000K时的谱线强度,如1-0带在3000,6000,10000K时的高温谱线带强度分别为1.58543×10-16 cm-1/(分子 cm-2)、6.07889×10-17 cm-1/(分子 cm-2)和2.3781×10-17 cm-1/(分子 cm-2)．这些结果对N2分子进一步的理论研究、实际应用和高温大气的建模与研究具都有一定的参考价值．     

Rovibrational dynamics of the RbCs molecule in static electric fields. Classical study

We study the classical dynamics of the RbCs molecule in the presence of a static electric field. Under the Born–Oppenheimer approximation, we perform a rovibrational investigation which includes the interaction of the field with the molecular polarizability. The stability of the equilibrium points and the phase space structure of the system are explored in detail. We find that, for strong electric fields or for energies close to the dissociation threshold, the molecular polarizability causes relevant effects on the system dynamics.     

High-resolution spectrum of the first triad of D<Subscript>2</Subscript><Superscript>32</Superscript>S interacting states

The high-resolution spectrum of the D₂S molecule registered with a Bruker IFS 120HR Fourier spectrometer in the range 2000–4200 cm^–1 is analyzed. The spectroscopic parameters of the (110), (011), and (030) vibrational states are obtained. They reproduce rotational energy levels with the accuracy close to experimental one (a total of 737 rovibrational energies is considered corresponding to 2590 transitions up to J ^max = 21). Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 3–7, February, 2009.     

Superexcited states of carbon monoxide studied by fast-electron impact

Absolute optical oscillator strength density and double differential cross section spectra of CO below 120 eV are determined by fast electron impact. Some peaks above the first ionization threshold stand out as the momentum transfer square K2 increases. The doubly excited Rydberg states converging to C 2∑^＋, D ^2∏, and F ^2∏ states of CO^＋, respectively, are confirmed in our spectra. Another peak at around 32eV is assigned to the transition of （3σ）^-1（2π）^1^1∏←X^1∑^＋.     

Quantum computing methods for electronic states of the water molecule

ABSTRACT

We compare recently proposed methods to compute the electronic state energies of the water molecule on a quantum computer. The methods include the phase estimation algorithm based on Trotter decomposition, the phase estimation algorithm based on the direct implementation of the Hamiltonian, direct measurement based on the implementation of the Hamiltonian and a specific variational quantum eigensolver, Pairwise VQE. After deriving the Hamiltonian using STO-3G basis, we first explain how each method works and then compare the simulation results in terms of gate complexity and the number of measurements for the ground state of the water molecule with different O–H bond lengths. Moreover, we present the analytical analyses of the error and the gate-complexity for each method. While the required number of qubits for each method is almost the same, the number of gates and the error vary a lot. In conclusion, among methods based on the phase estimation algorithm, the second-order direct method provides the most efficient circuit implementations in terms of the gate complexity. Moreover, Pairwise VQE serves the most practical method for near-term applications on the current available quantum computers. Finally the possibility of extending the calculation to excited states and resonances is discussed.     

Spectroscopic and molecular properties of 14 selected electronic states of Si2 molecule

The potential energy curves (PECs) of the X³Σ_g⁻, D³Π_u, a¹Δ_g, b¹Π_u, H′³Σ_u⁻, K³Σ_u⁻, 1³Σ_u⁺, 1³Π_g, 2³Σ_u⁺, 2³Π_g, 3³Π_g, 3³Σ_u⁺, 2³Π_u and 2³Σ_g⁻ electronic states of the Si₂ molecule are investigated using the complete active space self-consistent field (CASSCF) method followed by the valence internally contracted multireference configuration interaction (MRCI) approach with the correlation-consistent basis sets of Dunning and co-workers. The effects on the PECs by the core-valence correlation and relativistic corrections are included. The way to consider the relativistic correction is to use the third-order Douglas-Kroll Hamiltonian approximation. The core-valence correlation correction is made with the aug-cc-pCV5Z basis set. And the relativistic correction is performed at the level of cc-pV5Z basis set. To obtain more reliable results, the PECs determined by the MRCI calculations are also corrected for size-extensivity errors by means of the Davidson modification (MRCI+Q). The PECs of all these electronic states are extrapolated to the complete basis set limit by the total-energy extrapolation scheme. Using the PECs, the spectroscopic parameters are determined and compared with those reported in the literature. With these PECs determined by the MRCI+Q/CV+DK+56 calculations, the vibrational levels and inertial rotation constants of the first 20 vibrational states are evaluated and compared with the RKR data for these electronic states when the rotational quantum number J equals zero. On the whole, as expected, the most accurate spectroscopic parameters and molecular constants of the Si₂ molecule are determined by the MRCI+Q/CV+DK+56 calculations. And the spectroscopic parameters of the 1³Σ_u⁺, 1³Π_g, 2³Σ_u⁺, 2³Π_g, 3³Π_g, 3³Σ_u⁺, 2³Π_u and 2³Σ_g⁻ electronic states obtained by the MRCI+Q/CV+DK+56 calculations should be good prediction for future laboratory experiment.     

A review on the methods for correcting the fluorescence inner-filter effect of fluorescence spectrum

Fluorescence spectroscopy is frequently used to analyze the concentration of fluorescent materials in solution. However, in conventional fluorescence spectroscopy, the response between the fluorescence intensity and fluorophore concentration is nonlinear at high concentrations due to uncompensated inner-filter effects (IFE). Many methods to resolve this problem have been developed in recent decades. This review introduces the methods used to correct the IFE, including direct correction and parameter correction. Relevant detection parameters, including the materials, matrices, detection limits, detection instruments and relative standard deviations, are tabulated. The advantages and limitations of these correction techniques are also discussed. Finally, the methods used to correct for the IFE are summarized, and future research directions are discussed.     

用差分收敛法研究NaLi分子部分电子态的完全振动能谱

基于双核分子振动能级的普遍表达式和差分收敛法(difference converging method, DCM), 利用微分思想将DCM应用于双核分子体系完全振动能谱的研究中. 应用DCM方法, 分别选用实验上获得的一组(10条)精确的振动能级, 对NaLi分子3¹Π, 4¹Π 和A¹Σ⁺电子态进行了研究, DCM的研究结果正确重复了已知数据并预测出了在实验上未能获得的包含高激发态在内的完全振动能谱数据, 同时计算得到了这3个电子态的振动光谱常数.     

Anisotropic Stark effect of carbon monoxide: emergent orbital cooperativity

ABSTRACT

Applying external electric fields to molecules gives rise to spectral shifting and splitting, a phenomenon known as the Stark effect. However, a fundamental question of how electronic structures of molecules are modified by electric fields is still not well understood. By applying electric fields to a carbon monoxide molecule, herein we have successfully addressed the fundamental question at orbital scales and discovered that the Stark effect exhibits anisotropic characters depending on the direction of the electric fields with respect to the molecular axis. Based on the fact that applying electric fields along the molecular axis always preserved the orthogonality between the sigma and pi electrons, we found that orbital resemblance-based cooperativity can only operate within either the sigma system in which sigma electrons somehow prefer to resemble each other or the pi electron system in which the 1π electrons experience polarization-based self-resemblance. However, switching the electric field vertical to the molecular axis breaks down the orthogonality between the sigma system and pi electron systems, opening up electronic channels that allow σ electron systems to resemble π electrons. Such orbital cooperativity represents a new physical effect beyond the conventional Stark effect. Moreover, we have found that applying electric fields to the molecule would modify its molecular orbital diagram, depending on the directions of the electric fields; the electric field along the carbon-to-oxygen direction basically retains the MO diagram of the free CO molecule, with noticeable intra-orbital electron redistributions, whereas the oxygen-to-carbon electric field does create new states of molecular orbital contributions.     

Multireference configuration interaction study on spectroscopic properties of low-lying electronic states of As2 molecule

The potential energy curves (PECs) of four electronic states (X1Σ+g , e3△u , a 3 Σ-u , and d 3Πg ) of an As 2 molecule are investigated employing the complete active space self-consistent field (CASSCF) method followed by the valence internally contracted multireference configuration interaction (MRCI) approach in conjunction with the correlation-consistent aug-cc-pV5Z basis set. The effect on PECs by the relativistic correction is taken into account. The way to consider the relativistic correction is to employ the second-order Douglas-Kroll Hamiltonian approximation. The correction is made at the level of a cc-pV5Z basis set. The PECs of the electronic states involved are extrapolated to the complete basis set limit. With the PECs, the spectroscopic parameters (Te , Re , ωe , ωexe , ωeye , αe , βe , γe , and Be ) of these electronic states are determined and compared in detail with those reported in the literature. Excellent agreement is found between the present results and the experimental data. The first 40 vibrational states are studied for each electronic state when the rotational quantum number J equals zero. In addition, the vibrational levels, inertial rotation and centrifugal distortion constants of d 3Πg electronic state are reported which are in excellent agreement with the available measurements. Comparison with the experimental data shows that the present results are both reliable and accurate.     

太阳辐射计的衍射效应修正

太阳辐射测量是研究太阳活动与地球气候演变的重要方式之一,对人类社会的可持续发展具有重要意义。衍射效应作为测量过程中系统误差的主要来源之一,有必要进行精确的修正,从而提高测量数据的精度。首先,对衍射效应理论进行研究,从Kirchhoff衍射理论出发,在高斯光学近似下,逐步确定点与点,点与面,面与面之间的能量传输关系,推导出了衍射效应的一般公式;接着,根据衍射效应的渐近性质,得到了一种简化的计算方法;然后,用简化的方法计算太阳辐照绝对辐射计(SIAR)的衍射效应以及衍射修正因子,最后,根据衍射修正结果,计算相对于世界辐射基准(WRR)的定标系数。结果显示:SIAR的衍射效应以及衍射修正因子分别约为1.002 742和0.997 265。经过衍射修正后,SIAR对WRR的定标系数更接近于1,表明衍射修正降低了系统误差,提高了辐射测量的准确度。