Rotational analysis of the c3Πu–b3Πg system of P2

The rotationally resolved spectra of the c³Π_u–b³Π_g system of P₂ in the 16620–17860 cm^?1 region is reanalyzed here to obtain more assignments of the rotational lines and more accurate molecular constants. Approximately 500 spectral lines were assigned to six subbands: the Ω=0, 1 and 2 components of the (2, 3) band, the Ω=0 and 2 components of the (1, 3) band and the Ω=2 component of the (1, 2) band. Because of perturbations in the c³Π_u (υ=2) state, the Λ-doubling in the ³Π₂–³Π₂ subband of the (2, 3) band was resolved. By the weighted nonlinear least-squares fitting using two types of effective Hamiltonians, more accurate molecular constants for the υ′=1 and 2 levels in the c³Π_u state and for the υ″=2 and 3 levels in the b³Π_g state of P₂ were derived.     

Perturbation Facilitated Optical-Optical Double Resonance spectroscopy of the 6Li233Σg+, 23Πg, 13Δg,b3Πu,and a3Σu+ states

The technique, Perturbation Facilitated Optical-Optical Double Resonance, has provided spectroscopic access to and molecular constants for the 3³Σ_g⁺ (v = 1–9), 2³Π_g (v = 0–24), 1³Δ_g (v = 3–14), b³Π_u (v = 0–17), and a³Σ_u⁺ (v = 0–6) states of the ⁶Li₂ molecule. Perturbation Facilitated Optical-Optical Double Resonance takes advantage of two weak spin-orbit perturbations, A¹Σ_u⁺ (v = 2, J = 33) ∼ b³Π_u (v = 9, F₁, N = 32) and A¹Σ_u⁺ (v = 9, J = 20) ∼ b³Π_u (v = 15, F₁, N = 19), to excite from X¹Σ_g⁺ (v = 0 or 1) into single rotation-vibration levels of ³Λ_u (F₁ fine structure component only) via the spin-mixed intermediate levels. The ³Λ_u (F₁ only) states are sampled in resolved fluorescence spectra from Perturbation Facilitated Optical-Optical Double Resonance-populated ³Λ_g levels.     

钠双原子分子2^3Πu→1^3Σ^＋g跃迁近红外发射光谱

用紫外激光泵浦Ｎａ２分子高位电子态，观察到了位于０．９８－１．０４μｍ谱区峰值为１．０μｍ附近的近红外发射谱，判断基来源于单三重态分子间能量转移后的２＾３Πｕ→＾Σ＾＋ｇ跃迁。，     

CW Optical-Optical Double Resonance studies of the 23Πg, 33Πg, 43Πg+, and 13Δg Rydberg states of Na2

The 2³Π_g, 3³Π_g, 4³Σ_g⁺, and 1³Δ_g states of the Na₂ molecule are observed by sub-Doppler Perturbation Facilitated Optical-Optical Double Resonance (PFOODR) spectroscopy. Absolute vibrational assignments and molecular constants are obtained for two of these states (3³Π_g, v = 0–25 observed, and 4³Σ_g⁺, v = 3–5, 13, 14 observed). Tentative vibrational assignments and provisional molecular constants are obtained for the 2³Π_g (v = 43–89 observed) and 1³Δ_g (v = 31–35, 40, 46–51 observed) states. Spin-orbit, spin-spin, and hyperfine splittings are observed. The direct ³Λ_g⁺ → a³Σ_u, 2³Π_g ∼ 3³Π_g perturbation-induced, and collision-induced contributions of these four ³Λ_g states to the ubiquitous Na-vapor violet and ultraviolet emission bands are discussed.     

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.     

Calculation of molecular constants for the X 1Σ g + , A 1Σ u + , B 1Πu, and a 3Σ u + electronic states of 39K2

The molecular constants are calculated for the X ¹Σ _g ⁺ , A ¹Σ _u ⁺ , B ¹Π_u, and a ³Σ _u ⁺ and electronic states of a potassium dimer. The wave functions and vibrational energies necessary for calculating the molecular constants are determined by solving the radial wave equation with the use of potential energy curves constructed by the semiempirical method. The vibrational terms, the rotational constants, and the centrifugal distortion constants calculated from the potential curves are compared with those determined from the experimental data.     

Ab initio nonadiabatic calculation of the sensitivity coefficients for the X 1Σ g + → B 1Σ u + ; C 1Πu lines of H2 to the proton-to-electron mass ratio

Ab initio nonadiabatic calculations of the wavelengths λ_ij of the individual lines of the Lyman X ¹Σ _g ⁺ → B ¹Σ _u ⁺ and Werner X ¹Σ _g ⁺ → C ¹Π_u series of molecular hydrogen and corresponding sensitivity coefficients K _ij = dlnλ_ij/dlnγ have been performed. These quantities are necessary for testing a possible change in the proton-to-electron mass ratio γ = m _p/m _e in the process of cosmological evolution. The basic contribution to K _ij comes from the difference between the average kinetic energies of vibrations of combined states. Nonadiabatic interactions are important for a small number of locally-perturbed rovibrational levels of the B ¹Σ _u ⁺ and C ¹Π _u ⁺ states, for which change in K _ij that is caused by nonadiabatic effects reaches 14%, which can lead to a significant systematic shift in the estimate of the parameter γ.     

Formation of N2 C3Πu and B3Πg by dissociative recombination of Ar 2 + in Ar+N2 early afterglow

The hf pulse excited Ar + N₂ mixtures and early afterglow are investigated at total pressures from 266 to 1995 Pa using nitrogen of 0·05–0·5% concentration. The time-resolved intensity of Ar I atomic lines and N₂ (2nd pos., 1st pos. and 1st neg.) band systems exhibit an intense early afterglow (0·3 ms). Both the decay of electron densityn _e and that of molecular Ar ₂ ⁺ ions and enhancement of coefficient of dissociative recombination due to electron temperature decrease after the pulse lead to the formation of characteristic secondary maximum of Ar I spectral line and N₂ molecular band intensities in the momentt _m after cut-off the pulse. The values oft _m(B³_g)>t _m(C³_u)>t _m(Ar I) decrease with increasing total pressure and increase with growing concentration of N₂ in Ar. In the afterglow period the Ar ₂ ⁺ dissociatively recombine in 5p and 4p Ar states. As a result of radiative transitions the metastable Ar (³P_2,0) atoms are formed which consequently due to collisions with N₂ molecules create electronically excited N₂. With increasing nitrogen concentration this effect becomes less pronounced and at concentration of N₂ greater than 0·5% it is negligible.     

On the rotational intensity distribution in the a1Δg → X3Σg− magnetic dipole transition of oxygen molecule

The relative intensity distribution in the rotational structure of the a¹Δ_g → X³Σ_g⁻ magnetic dipole transition of molecular oxygen is examined. Use is made of experimental data obtained from the high-resolution (0.02 cm⁻¹) FTS recording of the 0-0 band published by C. Amiot and J. Verges (Canad. J. Phys. 59, 1391–1398 (1981)). Comparison of the experimental and theoretical intensities indicates that rotational linestrength formulas containing purely vibronic transition moments are inadequate and need to be supplemented by two additional parameters of rovibronic origin.     

Study on the A~2Π_(3/2u), B~2Δ_(3/2u), and X~2Π_(3/2g) states of Cl_2~+ including its isotopologues

Adopting the experimentally available vibrational constants in a recent analysis of the strong perturbation between the A22Π3/2u and BΔ3/2u states of Cl+2in the A–X band system [Gharaibeh et al. 2012 J. Chem. Phys. 137 194317], an unambiguous vibrational assignment of the bands reported previously is carried out. The equilibrium rotational constants Be and α e of the X2Π3/2g and A2Π3/2u states for35Cl+2and35Cl37Cl+and those of the B2Δ3/2u state for35Cl+2are obtained by fitting the experimental values of Bυ. In addition, the values of Be and α e of these three states for the minor isotopologues35Cl37Cl+and37Cl+2are predicted by employing the isotopic effect. The values of equilibrium internuclear distance Re of the three states for the three isotopologues are calculated as well.     

钠分子B 1Πu与2 1Σ+g间的碰撞激发转移

用HeCd激光器的4416nm线激发Na2分子到B1Πu电子态,记录了Na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NaNa2系统中的碰撞过程,Na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57×10-10cm3·s-1,而B1Πu的预解离率为27×106s-1。     

Probabilities of rovibronic transitions in the I 1Π g − , J 1Δ g − →C 1Π ± u systems of bands of the deuterium molecule

Probabilities of spontaneous rovibronic transitions I ¹Π _g ^? , v′ J′, J ¹Δ _g ^? , v′, J′→C ¹Π _u ^± , v″, J″ of the D₂ molecule (for vibrational and rotational quantum numbers v′=v″=0–3 and J′=1–9, J″=J′±1) have been obtained for the first time. They were determined using (1) the previously proposed nonadiabatic model, which takes into account the electron-rotational interaction of the upper levels; (2) the coefficients of expansion of wave functions of perturbed states in the Born-Oppenheimer basis, which were found from the experimental data on rovibronic terms; and (3) semiempirical b initio data on electronic transition dipole moments of the 3dπ¹Π_g→2pπ¹Π_u and 3dπδ¹Δ_g→2pπ¹Π_u transitions. The dependences of the transition probabilities on J′ for the same bands of both hydrogen isotopomers H₂ and D₂ were found to be identical. They represent monotone functions for R and P branches and functions with a maximum (minimum) for Q branches. The ratios of transition probabilities of different isotopomers for different branches of the same systems of bands and for the same branches of different systems of bands were found to be correlated. The semiempirical values obtained in the paper agree with the experimental values within the limits of the errors of their determination. The nonempirical values of transition probabilities agree with the experiment considerably worse.     

BF分子A~1Π→X~1Σ~ 带系与b~3Σ~ →a~3Π带系的Franck-Condon因子计算

在双原子分子核运动的波动方程中，计入分子的振转相互作用项，得出的波函数除与振动量子数有关外，还与转动量子数有关．用该波函数编程序计算了ＢＦ分子Ａ１Π→Ｘ１Σ＋带系和ｂ３Σ＋→ａ３Π带系的ＦｒａｎｃｋＣｏｎｄｏｎ因子．计算中转动量子数的取值由Ｊ＝０取至Ｊ＝２００，结果适用于低温、高温和强激波条件．     

用微扰增强双共振对Na2 2 3Πg和3 3Πg能级进行新观测

Na22^3Пg和3^3Пg态在34860cm^-1(相对基态Te)和3s+3d解离限之间的Ω=0，1，2能级进行了脉冲激光微扰增强双共振探测、观测到两个态之间强烈的相互微扰．给出忽略微扰情况下Ω=0能级的Tv和Bv。     

单态氧(1,0)1Δg→3∑g-近红外磷光的直接光谱观察

从光谱上直接观察了单态氧～1.07μm谱带。血卟啉、原卟啉、卟啉C和四氯四碘荧光素钠等含极性基团的光敏剂与非极性的四苯基卟吩在相同的溶剂中所产生的谱带形状有所不同,测量了β-胡萝卜素对单态氧的猝灭常数,与文献在1.27μm测得的数值一致。     

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]     

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.