Electronic Transition Moment Variation in the C2Π–X2Σ+ System of Boron Monoxide

The extensive band system belonging to the C²Π_r–X²Σ⁺ transition of boron monoxide (BO) molecule lying in the vacuum ultraviolet region (150–230 nm) has been recorded in emission in a hollow cathode glow. A few new bands involving high v′ levels of C state have been observed. The Franck–Condon factors and r‐centroids were computed for the C–X system. By correlating the measured intensities to theory, the (relative) variation of the C–X electronic transition moment with internuclear separation was examined.     

Einstein A coefficients and absolute line intensities for the E2Π–X2Σ+ transition of CaH

Einstein A coefficients and absolute line intensities have been calculated for the E²Π–X²Σ⁺ transition of CaH. Using wavefunctions derived from the Rydberg–Klein–Rees (RKR) method and electronic transition dipole moment functions obtained from high-level ab initio calculations, rotationless transition dipole moment matrix elements have been calculated for all 10 bands involving v′=0,1 of the E²Π state and v″=0,1,2,3,4 of the X²Σ state. The rotational line strength factors (Hönl–London factors) are derived for the intermediate coupling case between Hund's case (a) and (b) for the E²Π–X²Σ⁺ transition. The computed transition dipole moments and the spectroscopic constants from a recent study [Ram et al., Journal of Molecular Spectroscopy 2011;266:86–91] have been combined to generate line lists containing Einstein A coefficients and absolute line intensities for 10 bands of the E²Π–X²Σ⁺ transition of CaH for J-values up to 50.5. The absolute line intensities have been used to determine a rotational temperature of 778±3 °C for the CaH sample in the recent study.     

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.     

High resolution emission spectroscopy of the E2Π–X2Σ+ transition of SrH and SrD

Emission spectra of SrH and SrD have been studied at high resolution using a Fourier transform spectrometer. The molecules have been produced in a high temperature furnace from the reaction of strontium metal vapor with H₂/D₂ in the presence of a slow flow of Ar gas. The spectra observed in the 18 000–19 500 cm^?1 region consist of the 0–0 and 1–1 bands of the E²Π–X²Σ⁺ transition of the two isotopologues. A rotational analysis of these bands has been obtained by combining the present measurements with previously available pure rotation and vibration–rotation measurements for the ground state, and improved spectroscopic constants have been obtained for the E²Π state. The present analysis provides spectroscopic constants for the E²Π state as ΔG(½) = 1166.1011(15) cm^?1, B_e = 3.805503(32) cm^?1, α_e = 0.098880(47) cm^?1, r_e = 2.1083727(89) Å for SrH, and ΔG(½) = 839.1283(23) cm^?1, B_e = 1.918564(15) cm^?1, α_e = 0.034719(23) cm^?1, r_e = 2.1121943(83) Å for SrD.     

Vibrational Analysis of the A3Π0−X1Σ+ and B3Π1−X1Σ+ Subsystems of the GaBr Molecule

Abstract

The emission band spectrum of gallium monobromide has been excited in a dc hollow cathode discharge. bands of the ³Π_0,1?X¹Σ⁺ system, lying in the range from 340 to 370 nm have been recorded at high resolution and measured. The previous vibrational analysis has been revised and corrected. New vibrational assignment has been proposed and improved vibrational constants of the upper and lower electronic states have been determined.     

LiH分子X 1Σ+、 A 1Σ+和B 1Π态的势能函数

利用SAC/SAC-CI方法,使用D95(d)、6-311G**及cc-PVTZ等基组,对LiH分子的基态(X1Σ+)、第一激发态(A1Σ+)及第二简并激发态(B1Π)的平衡结构和谐振频率进行了优化计算.通过对三个基组的计算结果的比较,得出了D95(d)基组为三个基组中的最优基组的结论;使用D95(d)基组,利用SAC的GSUM(GroupSumofOperators)方法对基态(X1Σ+)、SAC-CI的GSUM方法对激发态(A1Σ+和B1Π)进行单点能扫描计算,用正规方程组拟合Murrell-Sorbie函数,得到了相应电子态的完整势能函数;从得到的势能函数计算了与基态(X1Σ+)相对应的光谱常数,结果与实验数据较为一致.     

碰撞诱导钠分子A1Σ+u→X1Σ+g的荧光光谱

用532.0 nm激光激发Na2分子到B1Πu电子态,记录了Na(3P)原子的跃迁和Na2分子的A1Σ+u-Χ1Σ+g的谱带.由Na与Na2激发态发射的光谱及其强度可以认定在Na-Na2系统中的碰撞过程,Na(3P)原子线是Na2(B1Πu)到Na(3P)的碰撞能量转移产生的,预解离过程也可产生原子线.而A1Σ+u-Χ1Σ+g谱带是由B1Πu到21Σ+g的碰撞转移后再由21Σ+g到A1Σ+u的辐射而引起的.在360℃,根据辐射衰变率和荧光强度,得到Na2(B1Πu)到Na2(21Σ+g)碰撞转移率系数为7.1×10-10 cm3s-1,而B1Πu的预解离率为2.3×106 s-1.     

Polarization spectroscopy of Na2 A1Σu+-b3Πu ← X1Σg+ intercombination bands

The A¹Σ_u⁺ ∼ b³Π_u perturbation of Na₂ in several high vibrational levels has been studied by polarization spectroscopy. Deperturbed molecular constants are given for the mutually interacting v_A = 26 ∼ v_b = 28 and v_A = 34 ∼ v_b = 34 vibrational levels.     

Rovibrational transition properties of the X1Σ+ and A1Π states of carbon monosulfide

Carbon monosulfide was detected in outer space by rovibrational spectroscopy of the X ¹Σ⁺ state and A ¹Π – X ¹Σ⁺ system. This work calculated the potential energy curves and dipole moment functions of the X ¹Σ⁺ ₀₊ and A ¹Π₁ states, and computed the transition dipole moments between the two states employing the CASSCF method, followed by the valence icMRCI approach. Core-valence correlation and scalar relativistic corrections were included. The extrapolation of potential energies to the complete basis set limit was performed. The spin-orbit coupling effect was included. The Einstein A coefficients, band origins, and oscillator strengths were calculated for the rovibrational transitions when J?≤?150. The rovibrational transitions of the X ¹Σ⁺ ₀₊ and A ¹Π₁ states became very weak when Δυ?≥?6. The Einstein A coefficients of vibronic emissions of the A ¹Π₁ – X ¹Σ⁺ ₀₊ system were large, indicating that the emissions were able to be measured easily through spectroscopy. Several rovibrational transitions of the A ¹Π₁ – X ¹Σ⁺ ₀₊ system were analysed in detail. The distribution of radiative lifetime varying as rotational quantum number was calculated. The results obtained in this work agree well with the available experimental values.     

The B 2Σ+–X 2Σ+ Transition of 12C17O+: The 2‐υ″ Progression

Abstract

Three new bands of the B ²Σ⁺–X ²Σ⁺ system of ¹²C¹⁷O⁺ have been investigated using conventional spectroscopic techniques. The spectra were observed in a graphite hollow‐cathode lamp by discharging molecular oxygen (enriched in about 45% of the ¹⁷O₂ isotope) under 1.0 Torr pressure. The rotational analysis of the 2–4, 2–5, and 2–6 bands was performed with the effective Hamiltonian of Brown (Brown et al., J. Mol. Spectrosc. 1979; 74: 294–318). Molecular constants were derived from a merge calculation, including both the current wavenumbers and the spectroscopic data published by the authors previously. The principal equilibrium constants for the ground state of ¹²C¹⁷O⁺ are ω_e=2185.9658(84), ω_e x _e = 14.7674(11), B _e=1.927001(38), α_e=1.8236(22)×10^?2, γ_e=?0.331(28)×10^?4, D _e=6.041(12)×10^?6, β_e=0.100(31)×10^?7 cm^?1, and the equilibrium constants for the excited state are σ_e=45876.499(15), ω_e=1712.201(12), ω_e x _e=27.3528(39), B _e=1.754109(35), α_e=2.8706(57)×10^?2, γ_e = ?1.15(19)×10^?4, D _e=7.491(20)×10^?6, β_e=2.13(12)×10^?7, γ_e = 2.0953(97)×10^?2, and α_γe=?9.46(59)×10^?4 cm^?1, respectively. Rydberg–Klein–Rees potential energy curves were constructed for the B ²Σ⁺ and X ²Σ⁺ states of this molecule, and Franck–Condon factors were calculated for the vibrational bands of the B–X system.     

Radiation Parameters for the Electronic Transition A2Π1/2–X2Σ+ of the Diatomic Exiplex CsXe

Journal of Applied Spectroscopy - The radiation parameters, e.g., Einstein coefficients, oscillator strengths, Frank–Condon factors, and wavenumbers of vibronic transitions in the system of...     

AlF的X1Σ+,A1Π和B1Σ+态的势能函数

使用SAC/SAC-CI和D95 、6-311 g及D95(d)等基组,分别对AlF的基态X1Σ 、第一简并激发态A1Π和第二激发态B1Σ 的平衡结构和谐振频率进行了优化计算.对所有计算结果进行比较,得出D95(d)基组为最优基组;运用D95(d)基组和SAC方法对基态X1Σ ,SAC-CI方法对激发态A1Π和B1Σ 进行单点能扫描计算,并用正规方程组拟合Murrell-Sorbie函数,得到了相应电子态的势能函数解析式,由得到的势能函数计算了与X1Σ 、A1Π和B1Σ 态相对应的光谱常数,结果与实验数据较为一致.     

Optically Forbidden Transition of A＇3Δu ← X3Σg-in Oxygen

The electron energy loss spectra for the valence-shell excitations of oxygen are measured at an incident electron energy of 2500 eV and at scattering angles from 4° to 8.5°. The dipole-forbidden and octupole-allowed transition of the A＇3Δu ←X3Σg- is observed from the measured spectra, and it is found that the peak profile of the A＇3Δu ←X3Σg^- excitation can be well represented by a Gaussin function. The energy position of 6.007±0.008 eV and Franck？Condon linewidth of 1.312±0.020 eV of the A＇3Δu ←X3Σg^-, which are independent of the scattering condition, have been determined for the first time. The peak profiles of the A＇3Δu ←X3Σg^- determined in this work provide a possibility to realize the spectral decomposition method of unfolding the Herzberg pseudocontinuum proposed by -ampbell ？t et al. [Phys. Rev. A 61 （2000） 022706]     

Argon ion laser-induced BaS B1Σ+-A1Σ+, A′1Π, a3Π, and X1Σ+ fluorescence spectra: Analysis of A ∼ A′, A ∼ a,and A′ ∼ a perturbations

The 333.6-, 351.1-, and 363.8-nm lines of a cw argon ion laser are found to coincide with the BaS B¹Σ⁺-X¹Σ⁺ (12, 0) R(17), (6, 0) P(35), and (3, 0) R(125) transitions, respectively. Fluorescence transitions from the laser-prepared upper levels terminating in X¹Σ⁺v = 0–28, A¹Σ⁺v = 1–3, A′¹Π v = 1–13, and a³Π₁v = 3–12 are assigned. These results are combined with a previous analysis of the extensively perturbed BaS A¹Σ⁺-X¹Σ⁺ system [R. F. Barrow, W. G. Burton, and P. A. Jones, Trans. Farad. Soc.67, 902–906 (1971)]. Every observed perturbation of the BaS A¹Σ⁺ state is electronically and vibrationally assigned. The levels a³Π₀v = 10–13, a³Π₁v = 12–14, a³Π₂v = 15, and A′¹Π v = 10–13 are sampled via their perturbations of A¹Σ⁺v = 0–2. Although the mutual interactions of the a³Π, A′¹Π, and A¹Σ⁺ states approach Hund's case (c) limit, a complete deperturbation is performed from a case (a) starting point. Of the five lowest energy electronic states of BaS, only b³Σ⁺ remains uncharacterized. Principal deperturbed molecular constants are (in cm^?1, 1σ uncertainties in parentheses):

     

17.

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

W. Szajna  M. Zachwieja  R. Kępa 《光谱学快报》2013,46(3):207-212

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.     

18.

Radial Functions of Diatomic Lithium Halides X 1Σ+ From Vibration-Rotational Spectra     

J. F. Ogilvie 《光谱学快报》2013,46(8):1341-1354

The radial functions for potential energy and adiabatic and nonadiabatic effects in the forms of polynomials with coefficients c_j, h_j ^Li, h_j ^X, g_j ^Li and g_j ^X of the reduced variable for internuclear distance z=2.(R-R_e)/(R+R_e) to various non-negative powers have been determined for the family of diatomic molecules of the lithium halides, LiF, LiCl, LiBr and LiI, with the corresponding results of LiH included for purposes of comparison. Trends are evident in the coefficients of lower order, but those of higher order are susceptible not only to the influence of the extent and quality of the data but also to the truncation of the power series in the representations. The various radial functions are valid with the specified ranges of internuclear distance depending on the maximum extent of vibrational excitation of the spectra.     

19.

The Cs2 A1Σu+ → X1Σg+ fluorescence excited by the Ar+ 1.09-μm laser line     

《Journal of Molecular Spectroscopy》1987,126(2):393-404

     

20.

A New Study of the Perturbations in theA1Π State of PN     

《Journal of Molecular Spectroscopy》1996,176(1):75-84

TheA¹Π–X¹Σ⁺system of the PN molecule has been reexamined via high resolution conventional spectroscopy, at higher rotationalJ-values than those in previous studies. It is shown that perturbations occurring in theA¹Π (v= 0 to 3) levels give access to information concerning the (e³Σ⁻,a³Σ⁺,d³Δ,C¹Σ⁻,D¹Δ) valence states. Of particular interest are (1) the strong spin–orbit interaction between thee³Σ⁻andA¹Π (v_A= 2) levels, yielding 17 rotational energy levels of thee³Σ⁻state, and (2) the triple crossing occurring between theA¹Π (v_A= 3),d³Δ, andC¹Σ⁻levels.     

	$\text{T}{}_{\mathrm{e}}$	$\text{ω}{}_{\mathrm{e}}$	$\text{ω}{}_{\mathrm{e}}\text{x}{}_{\mathrm{e}}$	$\text{B}{}_{\mathrm{e}}\text{× 10}{}^2$	$\text{α}{}_{\mathrm{e}}\text{× 10}{}^4$	$\text{R}{}_{\mathrm{e}}\text{(}\text{A}\text{?}\text{)}$
$\text{A}{}^1\text{Σ}{}^{\mathrm{+}}$	14 498.6(1)	287.7(1)	1.15(5)	9.365(5)	5.0(10)	2.633
$\text{A′}{}^1\text{Π}$	12 095(6)	258.9(5)	0.7	8.21(5)	3.6(5)	2.813
$\text{a}{}^3\text{Π}{}_{\mathrm{i}}$	11 835(6)	259.6(5)	0.7	8.21	3.6	2.813
$\text{X}{}^1\text{Σ}{}^{\mathrm{+}}$	0	379.50(4)	0.91(1)	10.334(1)	3.4(2)	2.507

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.     

Radial Functions of Diatomic Lithium Halides X 1Σ+ From Vibration-Rotational Spectra

The radial functions for potential energy and adiabatic and nonadiabatic effects in the forms of polynomials with coefficients c_j, h_j ^Li, h_j ^X, g_j ^Li and g_j ^X of the reduced variable for internuclear distance z=2.(R-R_e)/(R+R_e) to various non-negative powers have been determined for the family of diatomic molecules of the lithium halides, LiF, LiCl, LiBr and LiI, with the corresponding results of LiH included for purposes of comparison. Trends are evident in the coefficients of lower order, but those of higher order are susceptible not only to the influence of the extent and quality of the data but also to the truncation of the power series in the representations. The various radial functions are valid with the specified ranges of internuclear distance depending on the maximum extent of vibrational excitation of the spectra.     

A New Study of the Perturbations in theA1Π State of PN

TheA¹Π–X¹Σ⁺system of the PN molecule has been reexamined via high resolution conventional spectroscopy, at higher rotationalJ-values than those in previous studies. It is shown that perturbations occurring in theA¹Π (v= 0 to 3) levels give access to information concerning the (e³Σ⁻,a³Σ⁺,d³Δ,C¹Σ⁻,D¹Δ) valence states. Of particular interest are (1) the strong spin–orbit interaction between thee³Σ⁻andA¹Π (v_A= 2) levels, yielding 17 rotational energy levels of thee³Σ⁻state, and (2) the triple crossing occurring between theA¹Π (v_A= 3),d³Δ, andC¹Σ⁻levels.