氮化钒的选态双色可见紫外共振增强光电离和脉冲场光电子研究 (cited: 4)

对气态氮化钒(VN)分子在光子总能量为56900～59020 cm^-13∏0, v'=0)的单转动态, 然后再被紫外激光电离．这样的双色激光模式可以测量电子态、振动态和转动态都被选择和解析的氮化钒阳离子VN⁺(X²△; v⁺=0, 1, 2)光谱． 通过对转动解析的PFI-PE光谱模拟分析, 确定J⁺=3/2为基态离子态的最低转动能级, 从而确认VN⁺的基态电子态为²△_3/2．通过对VN+(PFI-PE)光谱的分析得到如下物理量的精确数值：VN⁺(X²△_3/2)的绝热电离能为IE(VN)=56909.5±0.8 cm^-1(7.05588±0.00010 eV),振动常数ω_e⁺=1068.0±0.8 cm^-1,反常振动常数ω_e⁺χ_e⁺=5.8±0.8 cm^-1;VN⁺(X²△_3/2)的转动常数B_e⁺=0.6563±0.0005 cm^-1,α_e⁺=0.0069±0.0004 cm^-1,平衡键长为1.529 ?;VN⁺(X²△_5/2)的转动常数B_e⁺=0.6578±0.0028 cm^-1,α_e⁺=0.0085±0.0028 cm^-1,平衡键长为1.527 ?;X²△_5/2,3/2自旋轨道耦合常数A=153.3±0.8 cm^-1     

SiO2分子的基态(X1A1)结构与分析势能函数

应用群论及原子分子反应静力学方法推导了SiO₂分子的电子态及其离解极限，采用B3P86方法，在6-311G^**水平上,优化出SiO₂基态分子稳定构型为单重态的C_2V构型，其平衡核间距R_e=R_Si—O=0.1587 nm,∠OSiO＝111.2°,能量为-440.4392 a.u..同时计算出基态的简正振动频率:对称伸缩振动频率ν(B₂)=945.4cm^-1，弯曲振动频率ν(A₁)=273.5 cm^-1和反对称伸缩振动频率ν(A₁)=1362.9cm^-1.在此基础上，使用多体项展式理论方法，导出了基态SiO₂分子的全空间解析势能函数，该势能函数准确再现了SiO₂(C_2V)平衡结构.     

OH, OCI, HOCI(1A')的从头算与势能曲线

采用Gassian09程序包中的多种方法对OH, OCI, HOCI分子的基态结构进行优化计算, 优选出QCISD/6-311G(2df), B3P86/6-311+G(2df)方法分别对OH(X²), OCI(X²)分子进行计算, 得到平衡核间距R_OH=0.09696 nm, R_OCI=0.1569 nm, 谐振频率ω(OH)=3745.37 cm^-1, ω(OCI)=892.046 cm^-1, 与实验结果非常符合. 用Murrell-Sorbie势能函数对OH和OCI分子的扫描势能点进行拟合, 其扫描点都与四参数Murrell-Sorbie函数拟合曲线符合得很好．优选出QCISD(T)/D95(df, pd)方法对HOCI分子进行计算, 得到基态为X¹A', 键长R_OH =0.0966 nm, 键角∠HOCI=102.3°, 谐振频率ω₁(a₁)=738.69 cm^-1, ω₂(b₂)=1260.25 cm^-1, 离解能D_e=2.24eV. 通过比较发现这些结果与实验值符合得很好,并优于文献报道的结果. 随后计算出了力常数, 在此基础上,推导出HOCI分子的多体展式势能函数.报道了HOCI分子对称伸缩振动势能图中在H+OCI →HOCI反应通道上有一鞍点, H原子需要越过1.74eV的能垒才能生成HOCI的稳定结构, 在Cl+OH→HOCI通道上不存在明显势垒, 容易形成稳定的HOCI分子.     

AsO+同位素离子X2∑+和A2∏电子态的多参考组态相互作用方法研究

采用包含Davidson修正多参考组态相互作用(MRCI)方法结合价态范围内的最大相关一致基As/aug-cc-pV5Z和O/aug-cc-pV6Z, 计算了AsO⁺ (X²∑⁺)和AsO⁺(A²∏)的势能曲线. 利用AsO⁺离子的势能曲线在同位素质量修正的基础上, 拟合出了同位素离子⁷⁵As¹⁶O⁺和⁷⁵As¹⁸O⁺的两个电子态光谱常数. 对于X²∑⁺态的主要同位素离子⁷⁵As¹⁶O⁺, 其光谱常数R_e, ω_e, ω_ex_e, B_e和α_e分别为 0.15770 nm, 1091.07 cm^-1, 5.02017 cm^-1, 0.514826 cm^-1和0.003123 cm^-1; 对于A²∏态的主要同位素离子⁷⁵As¹⁶O⁺, 其T_e, R_e, ω_e, ω_ex_e, B_e和α_e分别为5.248 eV, 0.16982 nm, 776.848 cm^-1, 6.71941 cm^-1, 0.443385 cm^-1和0.003948 cm^-1. 这些数据与已有的实验结果均符合很好. 通过求解核运动的径向薛定谔方程, 找到了J=0时AsO⁺(X²∑⁺)和AsO⁺(A²∏)的前20个振动态. 对于每一振动态, 还分别计算了它的振动能级、转动惯量及离心畸变常数, 并进行了同位素质量修正, 得到各同位素离子的分子常数. 这些结果与已有的实验值非常一致. 本文对于同位素离子⁷⁵As¹⁶O⁺(X¹∑⁺), ⁷⁵As¹⁸O⁺(X¹∑⁺), ⁷⁵As¹⁶O⁺(A¹∏)和⁷⁵As¹⁶O⁺(A¹∏)的光谱常数和分子常数属首次报导.     

SiN自由基X2∑+, A2Π和B2∑+ 电子态的光谱常数研究

采用内收缩多参考组态相互作用(MRCI)方法, 结合价态范围内的最大相关一致基aug-cc-pV6Z, 计算了SiN自由基X²∑⁺, A²Π 和B²∑⁺电子态的势能曲线. 采用Davidson修正来避免由于MRCI方法本身的大小一致性缺陷产生的误差. 为了提高计算精度, 进一步考虑了相对论修正和核价相关修正对势能曲线的影响. 本文的相对论修正是利用二阶Douglas-Kroll 哈密顿近似在cc-pV5Z基组水平进行的; 同时核价相关修正是在cc-pCV5Z基组水平进行的. 对这些势能曲线进行拟合, 得到各种水平下三个电子态的光谱常数(T_e, R_e, ω_e, ω_ex_e, α_e和B_e), 并详细分析了Davidson修正、相对论修正和核价相关修正对光谱常数的影响. 与其他理论结果和实验数据进行比较, 可知本文的结果更精确、更完整.     

OCS+分子经由B2∑+←X2∏跃迁的光解离谱

制备出确定旋轨态的OCS⁺(X²∏)离子,在260～325 nm波长范围内研究了OCS^{+经由B2∑+←X2∏_3/2(000)和B2∑+←X2∏_1/2(000,001)跃迁的分质量光解离谱．由光解离谱得到OCS+(B2∑+)电子态的光谱常数υ1(CS stretch)=828.9(810.4) cm-1,υ2(bend)=491.3 cm-1和υ3(CO stretch)=1887.2 cm-1．在B2∑+←X2∏跃迁谱中只能观察到B2∑+(010)←X2∏_1/2(000)跃迁的谱峰, 而观察不到B2∑+←X2∏_3/2(000)跃迁的谱峰． 用X2∏电子态的(000)2∏_1/2和(010)2∑+_1/2电子振动能级之间的K耦合解释了这种B2∑+的υ2弯曲振动模的激发对X2∏电子态的旋轨分裂分量(Ω=1/2,3/2)的相关性}     

碘分子两个新的“E”带离子对态

使用脉冲光学双共振方法研究了碘分子“E”带离子对态,激发光总能量范围为43180—43600cm^-1。实验获得了“E”带两个尚未见报道的离子对态E₁(13≤V′_(E1)≤17)和E₂(15≤V′_(E2)≤19),其中T_(e1)=41909.13±1.786cm^-1,T_{(e相似文献}   

7Li2(X1Σ+g)分子的振动能级、转动惯量及离心畸变常数

使用密度泛函理论B3LYP和B3P86，以及组态相互作用方法CCSD(T)和QCISD, 利用多个基组对⁷Li₂(X¹Σ⁺_g)分子的平衡核间距(R_e)、谐振频率(ω_e)和离解能(D_e)进行了计算, 发现在CCSD(T)/cc-PVQZ理论水平下得到的结果(R_{e相似文献}   

BF自由基X1∑+和a3∏态光谱常数和分子常数研究

采用内收缩多参考组态相互作用方法和相关一致基aug-cc-pV6Z, 对BF自由基X¹∑⁺和a³∏ 态的势能曲线进行了研究. 计算是在0.095---1.33 nm的核间距内进行的. 为获得更准确的结果, 计算中还考虑了Davidson修正、相对论修正及核价相关修正对势能曲线的影响. 相对论修正采用的方法是二阶DouglasKroll哈密顿近似, 修正计算是在cc-pV5Z基组水平上进行的. 核价相关修正使用的是cc-pCV5Z基组. 利用得到的势能曲线, 拟合出了各种修正下BF自由基X¹∑⁺和a³∏ 态的光谱常数D_e, R_e, ω_e, ω_ex_e, ω_ey_e, B_e和α_e、并与实验结果进行了比较. 结果表明: 考虑Davidson修正、相对论修正和核价相关修正后得到的光谱常数最接近实验结果. 利用修正后的势能曲线, 通过求解径向振转Schrödinger方程, 找到了转动量子数J = 0时这两个电子态的全部振动态, 并计算了每一电子态前20个振动态的振动能级、惯性转动常数和离心畸变常数, 其值与已有的实验结果较为一致. 本文得到的光谱常数和分子常数达到了很高的精度, 能为进一步的光谱实验提供可靠的参考.     

PH, PD和PT分子常数理论研究

采用内收缩多参考组态相互作用(MRCI)方法和包含Davidson修正(+Q) 的MRCI方法结合相关一致基aug-cc-pV5Z研究了PH (X³Σ^-, a¹Δ和A³∏)分子的势能曲线. 在同位素质量识别的基础上对势能曲线进行拟合, 得到PH, PD和PT分子各个电子态的光谱常数(T_e, R_e, ω_e, ω_ex_e, α_e和 B_e). 通过与已有实验数据的比较发现, 本文的结果与实验结果非常一致. 对于PH, PD和PT分子的Σ^-电子态, 计算得到了J = 0时的前12个振动态. 对于每一个振动态, 还分别计算了它的振动能级、惯性转动常数和离心畸变常数. 与其他理论结果和实验数据进行比较可知, 本文的结果更精确、更完整. 文中PD和PT分子的光谱常数和分子常数均属首次报导.     

用MRCI方法研究CS+同位素离子X2Σ+和A2Π态的光谱常数与分子常数

利用内收缩多参考组态相互作用方法和价态范围内的最大相关一致基aug-cc-pV6Z, 在0.05—0.60 nm的核间距范围内计算了CS⁺离子X²Σ+和A²Π态的势能曲线. 利用CS⁺离子的势能曲线并在同位素质量修正的基础上, 拟合出了X²Σ+和A²Π态的同位素离子^{1 关键词： 同位素识别 势能曲线 光谱常数 分子常数}     

Accurate ab initio study of low-lying electronic states of phosphorus nitride radical

This paper employs the highly accurate valence internally contracted multireference configuration interaction method to investigate the potential energy curves (PECs) for the ground state (X 1 Σ +) and two low-lying excited states (A 1 Π and D 1 of phosphorus nitride (PN) radical with the correlation-consistent basis set,aug-cc-pV6Z,in the valence range.Relativistic effects are considered in these calculations.The spectroscopic constants of the X 1 Σ + and A 1 Π states are calculated based on the PECs,and the results are in good accord with the available experimental data.The first 30 vibrational states for the X 1 Σ + state and the first 40 vibrational states for theA 1 Π state are determined when J=0.For each vibrational state,molecular constants G(υ),B(υ) and D(υ) are also attained.     

Fourier Transform Emission Spectroscopy of the FΣ-XΣ System of RuN

Emission spectra of RuN have been recorded at high resolution in the region 12 000-35 000 cm⁻¹ using a Fourier transform spectrometer. The molecules were excited in a ruthenium hollow cathode lamp in the presence of about 2.5 Torr of Ne and 5 m Torr of N₂. New bands with origins near 17 758.1, 18 866.4, 19 800.4 and 20 721.5 cm⁻¹ have been assigned as the 0-1, 0-0, 1-0, and 2-0 bands of a new ²Σ⁺-²Σ⁺ system with the lower state as the ground state. This transition has been labeled as F²Σ⁺-X²Σ⁺, with the F²Σ⁺ state arising from the 1σ²2σ²1π⁴1δ⁴4σ¹ configuration. A rotational analysis of these bands has been carried out and spectroscopic constants have been extracted. The principal equilibrium constants for the ground state of RuN are ΔG(1/2)″=1108.3235(22) cm⁻¹, B_e″=0.5545023(42) cm⁻¹, α_e″=0.0034468(57) cm⁻¹, r_e″=1.5714269(60) Å, while the equilibrium constants for the excited state are ω_e′=946.8471(40) cm⁻¹, ω_ex_e′=6.4229(14) cm⁻¹, B_e′=0.50085(21) cm⁻¹, α_e′=0.00375(10) cm⁻¹, r_e′=1.65345(34) Å. This transition is analogous to the E²Σ⁺-X²Σ⁺ system of RhC (W. J. Balfour et al., J. Mol. Spectrosc.198, 393 (1999)).     

Rotationally resolved state-to-state photoelectron study of zirconium monoxide cation (ZrO+)

Using two-colour visible (Vis)–ultraviolet (UV) photoionisation and pulsed field ionisation–photoelectron (PFI–PE) methods, we have obtained cleanly rotationally resolved photoelectron spectra for ZrO⁺(X ²Δ_3/2,5/2; v⁺ = 0, 1, and 2). The rotation assignment of these state-to-state Vis–UV–PFI–PE spectra has allowed the unambiguous determination of the ground state term symmetry for ZrO⁺(X) to be ²Δ_3/2, and the adiabatic ionisation energy of ⁹⁰Zr¹⁶O, IE(⁹⁰Zr¹⁶O) = 54,948.3(8) cm^?1 [6.81272(10) eV]. The symmetry of the ionic ZrO⁺(X ²Δ_3/2) ground state determined here disagrees with that reported in previous experiments. The rotational and vibrational constants determined in this experiment for the ionic ⁹⁰Zr¹⁶O⁺(X ²Δ_3/2) ground state are: B_e⁺ = 0.4343(8) cm^?1 and α_e⁺ = 0.0019(5) cm^?1, and ω_e⁺ = 991.2(8) cm^?1 and ω_e⁺x_e⁺ = 3.5(8) cm^?1; and those for the ionic ⁹⁰Zr¹⁶O⁺(X ²Δ_5/2) excited spin-orbit state are: B_e⁺ = 0.4357(6) cm^?1 and α_e⁺ = 0.0022(4) cm^?1, and ω_e⁺ = 991.9(8) cm^?1 and ω_e⁺x_e⁺ = 3.6(8) cm^?1, respectively. Based on the latter B_e⁺ value, the equilibrium bond distances are determined to be r_e⁺ = 1.691(2) Å for ⁹⁰Zr¹⁶O⁺(X ²Δ_3/2) and r_e⁺ = 1.688(1) Å for ⁹⁰Zr¹⁶O⁺(X ²Δ_5/2). The IE(ZrO) along with the spectroscopic constants obtained here are valuable for benchmarking the ab initio quantum chemical calculations for energetic and structural predictions of ZrO/ZrO⁺.     

New analysis of the Douglas-Herzberg system (A1Π- X1Σ+) in the CH+ ion radical

Three bands of the A¹Π- X¹Σ⁺ system in the ¹²CH⁺ ion radical have been rephotographed under high resolution as an emission spectra using a Geissler-type discharge tube. The conventional technique of spectroscopy has been implemented. Using the Th lines as a standards, as well as an interferometric comparator equipped with a photoelectric scanning device, the 0-0 , 0-1 and 2-1 bands have been reanalyzed. By means of much longer bands (J_max = 17 in the Q(J) branch of the 0-0 band; J_max = 16 in the R(J) branch of the 0-1 band; J_max = 14 in the P(J) and Q(J) branches of the 2-1 band), than have been observed so far, as well as the merged calculations, using another five bands given by Carrington et al. [A. Carrington, D.A. Ramsay, Phys. Scripta 25, 272 (1982)] additionally, more accurate molecular constants for the X¹Σ⁺ state, the improved reduced band system origin T_e = 24118.726 (14) cm^-1 as well as for the first time the equilibrium molecular constants with their one standard deviation for the A¹Π state in the CH⁺ molecule have been computed: ω_e'=1864.402(22), ω_ex_e'=115.832(14), ω_ey_e'= 2.6301(24), B_e'=11.88677(72), α_e'= 0.9163(18), γ_e'= -2.29(12)×10^-2, ε_e'= 4.95(20)×10^-3, D_e'=1.92960(31)×10^-3, β_e'= 1.0733(50)×10^-4, δ_e'= -1.312(16)×10^-5, , α_qe'= -3.14(16)×10^-3, and q_De'= -2.20(14)×10^-5 cm^-1. Only in our research the addition to the zero-point energy Y'₀₀=-1.9430 cm^-1 and cm^-1 have been calculated. The equilibrium bond lengths of r'_e=1.235053(37) ? and ? for the A¹Π and X¹Σ⁺ states, respectively have been computed. Full quantum-mechanics characteristic of the A-X bands system in the ¹²CH⁺ molecule, i.e. RKR turning points, the Franck-Condon factors and r-centroids have been obtained. Dissociation energies D_e^{X1 Σ+}=(38470± 3503) cm^-1 and D_e^{A1 Π}= (14415 ±3509) cm^-1 for the molecule under consideration have been estimated.     

Rotational Analysis of the 1–4 Band of the B 2Σ+–X 2Σ+ System of 14C16O+

ABSTRACT

High-resolution emission spectrum of the 1–4 band of the B ²Σ⁺–X ²Σ⁺ transition of ¹⁴C¹⁶O⁺ was observed for the first time by conventional emission spectroscopy. The band spectrum was excited in a water-cooled Geissler lamp filled with commercial gaseous carbon monoxide enriched in about 80% of the radiocarbon ¹⁴C. A rotational analysis has been carried out and obtained molecular constants have been merged with previously published data for the B ²Σ⁺–A ²Π_i and A ²Π_i–X ²Σ⁺ transitions. The principal equilibrium constants for the ground X ²Σ⁺ state obtained from this work are ω_e = 2121.7726(98), ω_e x _e = 13.9055(27), B _e = 1.815290(30), α_e = 1.6594(33) × 10^?2, and γ_e = ? 0.377(73) × 10^?4 cm^?1. Also, presently known experimental equilibrium molecular constants of the X ²Σ⁺ states of the CO⁺ isotopic molecules are summarized and isotopic dependence of the B _e and ω _e constants is discussed.     

The spectra and structure of indium iodide: The rotational and vibrational constants of the A0 state

The rotational constants of the A0⁺ state of InI are reported for the first time as B_e = 0.038077 cm⁻¹ and α_e = 0.0002373 cm⁻¹, while T_e = 24402.91 cm⁻¹ for the A0⁺-X0⁺ transition. Accurate vibrational constants for both the A0⁺ and X0⁺ states are computed from the derived band origins.     

MRCI study on spectroscopic and molecular properties of four low-lying electronic states of the BO radical

The potential energy curves (PECs) of four low-lying electronic states of the BO radical, including two ²Σ⁺ and two ²Π states, have been studied using the full valence complete active space self-consistent field (CASSCF) method followed by the highly accurate valence internally contracted multireference configuration interaction (MRCI) approach in combination with the cc-pV5Z basis set for internuclear separations from 0.05 to 2.0 nm. The effect on the PECs by the relativistic correction has been taken into account. With these PECs, the spectroscopic parameters (T_e, D₀, D_e, R_e, ω_e, ω_ex_e, α_e and B_e) of two main isotopologues (¹¹B¹⁶O and ¹⁰B¹⁶O) have been determined. These parameters have been compared in detail with those of previous investigations reported in the literature, and excellent agreement has been found between the available data and the present results. By solving the radial Schrödinger equation of nuclear motion, 60 vibrational states for the ¹¹B¹⁶O(X²Σ⁺), 60 for the ¹⁰B¹⁶O(X²Σ⁺), 66 for the ¹¹B¹⁶O(A²Π) and 64 for the ¹⁰B¹⁶O(A²Π) are predicted for the non-rotating molecule. For each vibrational state of the ¹¹B¹⁶O(X²Σ⁺), ¹⁰B¹⁶O(X²Σ⁺), ¹¹B¹⁶O(A²Π) and ¹⁰B¹⁶O(A²Π), the vibrational level G(υ), inertial rotation constant B_υ and centrifugal distortion constant D_υ have been determined. Comparison with the available data shows that the present molecular constants are reliable and accurate. The ro-vibrational levels have been calculated for the X²Σ⁺ and A²Π states of two main species for future laboratory research.     

High-resolution study of the bΣ(b0)→XΣ(X10) transition of PI

Emission spectra of the b¹Σ⁺(b0⁺)→X³Σ⁻(X₁0⁺) transition of phosphorus iodide have been measured with a high-resolution Fourier-transform spectrometer. The PI radicals were generated and excited in a fast-flow system by reaction of phosphorus vapor (P_x) with iodine and microwave-discharged oxygen. Four sequences, Δv=0,+1,−1,−2, of the b¹Σ⁺(b0⁺)→X³Σ⁻(X₁0⁺) transition of PI comprising 28 bands were observed. Six bands were measured at high spectral resolution. Vibrational and rotational analyses have yielded accurate spectroscopic constants of the X₁0⁺ and b0⁺ states (in cm⁻¹): X₁0⁺: ω_e=371.296(4), ω_ex_e=1.3302(9), B_e=0.1194117(2), α_B=−0.0005676(7), D_e=4.56(2) ×10⁻⁸; b0⁺: T_e=11136.921(4), ω_e=400.165(6), ω_ex_e=1.345(2), B_e=0.1239237(2), α_B=−0.0005540(2), D_e=4.84(5) × 10⁻⁸, where the numbers in parentheses are the standard deviations of the parameters. No emissions of the b0⁺→X₂1 sub-system nor of the a¹Δ(a2)→X³Σ⁻(X₂1) transition have been observed leaving PI the only group Va halide for which the spin splitting in the X³Σ⁻ ground state is still unknown.