Laser Stark and diode laser spectroscopy of the 10-μm bands of CH2NH: Determination of the dipole moment orientation

The complexities apparent in the laser Stark spectra obtained from the 10-μm band system of CH₂NH are shown to be due to the interplay of the a and b components of the Coriolis and Stark effect coupling. As a result it has been possible to determine the relative orientations of the a and b components of the permanent electric dipole moment. This is analogous to the determination of the relative signs of the dipole moment derivatives from the analysis of the intensity perturbations produced by Coriolis interaction.A detailed comparison has also been made of the uses of laser Stark, diode laser, and Fourier transform spectroscopy for studying heavily perturbed molecular spectra.     

Measurement of nuclear moments and radii by collinear laser spectroscopy and by β-NMR spectroscopy

Experiments using laser spectroscopy and nuclear magnetic resonance techniques have been performed at ISOLDE on the unstable isotopes of several light elements. The results include nuclear ground state spins, magnetic dipole and electric quadrupole moments, and the behaviour of mean square nuclear charge radii within isotopic strings. These give important information about the nuclear structure at shell closures and close to the drip lines. This revised version was published online in July 2006 with corrections to the Cover Date.     

Spectroscopic study of B2Σ+–X1 2Π1/2 transition of electron electric dipole moment candidate PbF

PbF, a valuable candidate for measuring the electron electric dipole moment (eEDM), is of great significance in measuring its spectrum and deriving its molecular constants in experiment. In the present work, the rovibronic spectrum of the B$^{2}{\Sigma }^{+}$-X$_{1}^{\, 2}{\Pi }_{1/2}$ transition of PbF in a wavelength range of 260 nm-285 nm is studied by the laser ablation/laser induced fluorescence method. The molecular parameters of the X$_{1}^{\, 2}{\Pi }_{1/2}$ (${v'}=0)$ and B$^{2}{\Sigma }^{+}$ (${v}'=0, 1$) states are derived from the recorded spectra of the (0, 0) and (1, 0) bands of the B$^{2}{\Sigma }^{+}$-X$_{1}^{\, 2}{\Pi }_{1/2}$ transition. Also, the Franck-Condon factors (FCFs) of the transitions between the B$^{2}{\Sigma }^{+}$ and X$_{1}^{\, 2}{\Pi }_{1/2}$ states are calculated by the RKR/LEVEL method and the Morse potential method, respectively.     

Measurement of the electric form factor of the neutron at Q2 = 0.3-0.8 (GeV/ c) 2 ⋆

The electric form factor of the neutron, G_E,n, has been measured at the Mainz Microtron by recoil polarimetry in the quasielastic D(¯e, e¯n)p reaction. Three data points have been extracted at squared four-momentum transfers Q ² = 0.3, 0.6 and 0.8 (GeV/c)². Corrections for nuclear binding effects have been applied.This revised version was published online in March 2005. In the previous version, the email address of one author was inadvertently assigned to multiple authors.     

The dipole moment function of CO(a 3Π)

The dipole moment function of the a ³Π state of CO is calculated using the multi-configuration self-consistent-field method of Wahl and Das. Only the dominant valence charge-transfer correlation configurations are mixed with the Hartree-Fock configuration since only the region between the classical turning points of the v = 1 vibrational level is considered. The calculated function does not agree with the shape of the fitted dipole moment function of Wicke et al. Configurations chosen on the basis of the model of optimized valence configurations do not determine an accurate dipole moment function for an open shell system.     

Study of the electric field and wall voltage in a high pressure ac-PDP cell by laser induced fluorescence spectroscopy

The electric field in a surface discharge type ac-PDP cell with He or He/Xe(0.1%) mixture has been measured over a wide range of pressure (5－50 kPa) using laser induced fluorescence detection. The wall voltage was estimated from the measured electric field. The Stark manifolds of triplet atomic helium Rydberg state (2s^3S) with principal quantum numbers (n=8 and 9) have been used to measure the electric field, as the lifetime of 2s^3S is longer than the single atomic helium Rydberg state (2s^1S) in high pressure discharge. Comparison of the Stark manifolds between the n=9 and n=8 shows that the measurement accuracy of electric field can be increased by 10%. The maximum electric field strength during discharge and the wall voltage at the end of pulse decreases with the increase of pressure. The comparison of He and He/Xe(0.1%) discharge at 13 kPa showed that He/Xe gas mixture discharge can accumulate more wall charge on MgO surface and the electric field was somewhat higher than those of pure helium discharge during pulse off period under the same discharge conditions.     

Direct observation of the anomalous zeeman effect at the X → B transition of molecular iodine by the method of nonlinear laser spectroscopy

Direct observation of the magnetic structure of transitions in molecular iodine is first reported. Using the method of saturated absorption spectroscopy in an external cell with I₂ vapour located in a longitudinal magnetic field we resolved the magnetic structure of the components of the hyperfine structure of the transition

Infrared tunable diode laser spectroscopy of the Δv = 2 band of 7Li127I

The high-resolution infrared spectrum of the Δv = 2 transitions of ⁷LiI has been measured at temperatures near 1050 K. The observations include vibrational transitions ranging from 2-0 to 10-8. The data were fit to a set of Dunham potential constants complete through the a₆ term, from which the Dunham rovibrational constants were calculated. The band centers for the v = 1-0 and v = 2-0 transitions were determined to be 491.17398 ± 0.00026 cm⁻¹ and 976.73042 ± 0.00038 cm⁻¹, respectively.     

The magnetic dipole transitions in the (c) binding system

The magnetic dipole transitions between the vector mesons B-c and their relevant pseudoscalar mesons B c (B c ,B-c ,B c (2S ),B-c (2S ),B c (3S ),B-c (3S ) etc.,the binding states of (c) system) of the B c family are interesting.The ‘hyperfine’ splitting due to spin-spin interaction is an important topic for understanding the spin-spin interaction and the spectrum of the the (c) binding system.The knowledge about the magnetic dipole transitions is also very useful for identifying the vector boson B-c mesons experimentally,whose masses are just slightly above the masses of their relevant pseudoscalar mesons B c .Considering the possibility to observe the vector mesons via the transitions at Z 0 factory and the potential use of the theoretical estimate on the transitions,we fucus our efforts on calculating the magnetic dipole transitions,i.e.a precise calculation of the rates for the transitions such as decays B-c → B c γ and B-c → B c e + e-,and particularly work in the Bethe-Salpeter framework.As a typical example,we carefully investigate the dependence of the rate Γ(B-c → B c γ) on the mass difference ΔM = M B-c-M B c .     

Diode laser spectroscopy of the ν4 (HCN bend) band of HCNH+

The ν₄ (HCN bend) band of the HCNH⁺ ion has been observed by diode laser spectroscopy using a magnetic field modulation technique. Twenty-three Q-, P-, and R-branch lines were observed and analyzed to yield the rotational, centrifugal distortion, and l-type doubling constants for the ν₄ state. The band origin was determined to be 801.5934(6) cm⁻¹.     

Infrared laser magnetic resonance spectroscopy of the ν3 fundamental and associated hot bands of the NCO free radical

The v₃ = 1 ← 0 (out-of-phase stretching vibration) transition wavenumbers of gas-phase NCO have been measured, in many cases with sub-Doppler resolution, by mid-infrared laser magnetic resonance (LMR) spectroscopy. In addition to the fundamental transition from the ²Π ground vibronic state, hot bands from the v₂ = 1 ²Σ and ²Δ and from the v₂ = 2 ²Φ vibronic states were detected and analyzed. The ²Σ vibronic level, with a spin-orbit coupling only partly quenched by the Renner-Teller effect, is characterised by complex and rapid tuning of energies in the magnetic field. This is the first successful analysis of magnetic resonance spectra for non-unique Renner-Teller vibronic states. The new LMR transitions were combined with data from previous studies and analysed, using an effective Hamiltonian in a 40-parameter fit to 660 transitions and combination differences. Several new coupling parameters are required, having magnitudes generally consistent with predictions from standard vibration-rotation theory.     

Determination of the magnetic susceptibility of “poor” conductors by electron paramagnetic resonance

We consider a method for determining the magnetic susceptibility of “poor” conductors using electron paramagnetic resonance data. A method is described on the basis of double integration of the positive part of the derivative of the absorption line that has a Dyson shape. The skin depth is taken into account. Analysis is carried out for germanium samples doped by arsenic in the range of high concentrations corresponding to the insulator-metal transition.     

Ordering of the O(2)…D… O(2) bonds near the phase transition in KD3(SeO3)2 single crystals by D nuclear magnetic resonance

Deuterium resonance investigations of KD₃(SeO₃)₂ single crystals have been performed near the phase transition temperature T _C . There are two types of deuterium bonds in these crystals with different behaviors at this phase transition. Our experimental results show that there are significant changes in the D spinlattice relaxation time T ₁ at T _C ; the abrupt decrease in T ₁ near T _C can be explained by the critical slowing down of an overdamped soft pseudospin-type deuteron mode. Further, the ordering of the O(2)…D… O(2) bonds is affected by the phase transition, whereas the ordering of the O(1)-D… O(3) bonds is unaffected. The D NMR measurements also show that the D(2) deuteron disordering above T _C is dynamic and not static.     

CO laser-microwave double-resonance spectroscopy of H2CO with intense Stark field: Precise measurement of dipole moment in the ground and ν2 vibrational states

Stark-shifted microwave transitions in the ground and ν₂ vibrational states of H₂CO were observed by means of CO laser-microwave double-resonance with intense electric field. High sensitivity and precision were attained by the use of multireflection absorption cell, optical-flat Stark plates, and microwave frequency stabilization. Dipole moments determined from some individual rotational transitions in the ground and ν₂ vibrational states are, in Debye, with uncertainties in parentheses,

     

16.

New basis sets for the evaluation of the CO–Ne van der Waals complex interaction induced electric dipole moment and polarizability surfaces     

《Molecular physics》2012,110(19-20):2503-2512

Using the coupled cluster singles and doubles method together with the recently developed LPol-n (n?=?ds, dl, fs, fl), the aug-pc-2, the SVPD, the TZVPD and Dunning's x-aug-cc-pVXZ basis sets, we calculate the interaction induced electric dipole moment and polarizability of the CO–Ne van der Waals complex. We consider the effect of extending the bases with different sets of mid-bond functions, and after a systematic basis set study carried out at a representative set of intermolecular geometries, we select the aug-cc-pVTZ, the aug-pc-2, the LPol-fs and the TZVPD bases with a set of 3s3p2d1f1g mid-bond functions placed in the middle of the van der Waals bond for the evaluation of the whole interaction induced property surfaces. After having determined the optimal parameters of appropriate analytical functions fitting the interaction induced properties, the resulting surfaces are used in semiclassical calculations of the dielectric and refractivity second virial coefficients of the system. All through this study the results obtained with Dunning's basis set hierarchy and reported in Phys. Chem. Chem. Phys., 11, 9871 (2009) are taken as reference.     

17.

Pressure broadening of the ground vibrational state J = 31→J = 32 transition of CH3F by coincidence laser spectroscopy     

《Infrared physics》1989,29(6):1013-1019

We have studied self-broadening and foreign gas broadening of the ground state J = 31→J = 32 transition of CH₃F using a coincidence with the 184.3 μm emission from an optically pumped CH₂F₂ laser. Experiments have been carried out with polar and non-polar species as well as the noble gases.This transition is in the region where the classical rotation period is of the same order as the duration of a collision. The measurements indicate an anomalously low value of 7.0 MHz/Torr for the self-broadening coefficient of CH₃F and an unusually large value for the CH₃OH broadening coefficient. The latter is believed to be due to the presence of a low energy OH torsional model in CH₃OH.     

18.

Variation of electronic transition moment versus internuclear distance for NO (A2∑→ X2∏) transition   总被引：2，自引：2，他引：0  

张连水  张贵银  杨晓冬  赵晓辉  李裔 《中国光学快报(英文版)》2003,1(8)

Two-photon laser-induced fluorescence spectrum (TP-LIF) of NO is obtained with a Nd:YAG pumpedoptical parametric generator and amplifier as radiation source. Spectral intensity distribution shows thatthe electronic transition moment for NO (A2∑→ X2∏) transition varies significantly with inter-nucleardistance. The variation relationship of the electronic transition moment versus inter-nuclear distance isdeduced with polyminal fit procedure. The spontaneous radiative coefficients for NO (A2∑→ X2∏)transition from v′ = 0, 1 are obtained by combing this transition moment variation with the measurementsof spontaneous radiative lifetime.     

19.

One-electron pseudo-potential investigation of NO(X2Π)–Arn clusters (n = 1,2,3,4)     

H. Hammami  D. Mohamed  M. Ben El Hadj Rhouma  M. M. Al Mogren  M. Hochlaf 《Molecular physics》2017,115(20):2586-2596

     

20.

Infrared diode laser spectroscopy of the ν2 fundamental band of SH3+     

《Journal of Molecular Spectroscopy》1987,126(1):177-182

The high-resolution absorption spectrum of the ν₂ fundamental band of SH₃⁺ has been observed with the magnetic field modulation technique. The ions were generated in a hollow cathode discharge through a mixture of H₂ and H₂S. The molecular constants in the excited vibrational state are determined through a least-squares fit of the data to a standard symmetric top energy level expression. The anomalous sign of the centrifugal distortion constants is explained by the Coriolis interaction between the v₂ = 1 and v₄ = 1 states.     

Transition		G.S.		$\text{ν}{}_2$		δμ
110 ← 111		2.3315 (1)		2.3472 (1)		0.0157 (1)
211 ← 212		2.3313 (1)		2.3471 (1)		0.0158 (1)
312 ← 313		2.3313 (1)		2.3470 (1)		0.0157 (1)
826 ← 827		2.3311 (1)		2.3466 (1)		0.0155 (1)
927 ← 928		—		2.3466 (1)		—

New basis sets for the evaluation of the CO–Ne van der Waals complex interaction induced electric dipole moment and polarizability surfaces

Using the coupled cluster singles and doubles method together with the recently developed LPol-n (n?=?ds, dl, fs, fl), the aug-pc-2, the SVPD, the TZVPD and Dunning's x-aug-cc-pVXZ basis sets, we calculate the interaction induced electric dipole moment and polarizability of the CO–Ne van der Waals complex. We consider the effect of extending the bases with different sets of mid-bond functions, and after a systematic basis set study carried out at a representative set of intermolecular geometries, we select the aug-cc-pVTZ, the aug-pc-2, the LPol-fs and the TZVPD bases with a set of 3s3p2d1f1g mid-bond functions placed in the middle of the van der Waals bond for the evaluation of the whole interaction induced property surfaces. After having determined the optimal parameters of appropriate analytical functions fitting the interaction induced properties, the resulting surfaces are used in semiclassical calculations of the dielectric and refractivity second virial coefficients of the system. All through this study the results obtained with Dunning's basis set hierarchy and reported in Phys. Chem. Chem. Phys., 11, 9871 (2009) are taken as reference.     

Pressure broadening of the ground vibrational state J = 31→J = 32 transition of CH3F by coincidence laser spectroscopy

We have studied self-broadening and foreign gas broadening of the ground state J = 31→J = 32 transition of CH₃F using a coincidence with the 184.3 μm emission from an optically pumped CH₂F₂ laser. Experiments have been carried out with polar and non-polar species as well as the noble gases.This transition is in the region where the classical rotation period is of the same order as the duration of a collision. The measurements indicate an anomalously low value of 7.0 MHz/Torr for the self-broadening coefficient of CH₃F and an unusually large value for the CH₃OH broadening coefficient. The latter is believed to be due to the presence of a low energy OH torsional model in CH₃OH.     

Variation of electronic transition moment versus internuclear distance for NO (A2∑→ X2∏) transition

Two-photon laser-induced fluorescence spectrum (TP-LIF) of NO is obtained with a Nd:YAG pumpedoptical parametric generator and amplifier as radiation source. Spectral intensity distribution shows thatthe electronic transition moment for NO (A2∑→ X2∏) transition varies significantly with inter-nucleardistance. The variation relationship of the electronic transition moment versus inter-nuclear distance isdeduced with polyminal fit procedure. The spontaneous radiative coefficients for NO (A2∑→ X2∏)transition from v′ = 0, 1 are obtained by combing this transition moment variation with the measurementsof spontaneous radiative lifetime.     

Infrared diode laser spectroscopy of the ν2 fundamental band of SH3+

The high-resolution absorption spectrum of the ν₂ fundamental band of SH₃⁺ has been observed with the magnetic field modulation technique. The ions were generated in a hollow cathode discharge through a mixture of H₂ and H₂S. The molecular constants in the excited vibrational state are determined through a least-squares fit of the data to a standard symmetric top energy level expression. The anomalous sign of the centrifugal distortion constants is explained by the Coriolis interaction between the v₂ = 1 and v₄ = 1 states.