High-resolution Fourier spectrometry of 15N2 infrared emission spectrum: Extensive analysis of the B3Πg-A3Σu+ system

The emission spectrum of the B³Π_g-A³Σ_u⁺ system of the ¹⁵N₂ molecule was recorded between 3500 and 12 500 cm⁻¹ with a high-resolution Fourier spectrometer. Twelve bands with 0 < v′ < 5 and 0 < v″ < 9 are analyzed. The molecular parameters of the B³Π_g and A³Σ_u⁺ states are obtained by a complete fitting procedure. Derived values of equilibrium constants are deduced; the Franck-Condon factors are calculated for the B-A system of ¹⁵N₂.     

HSSH revisited: The high-resolution Fourier transform spectrum of the ground state between 30 and 90 cm−1

The spectrum of disulfane (HSSH) between 30 and 380 cm⁻¹ has been recorded in absorption using a new high-resolution Fourier transform spectrometer at the Justus-Liebig Universität Giessen. The spectrometer is briefly described, as well as procedures concerning the synthesis and handling of this quasi-stable species. A combined analysis of previous microwave data on the HSSH ground state and over 600 newly assigned lines between 30 and 90 cm⁻¹ has been carried out, yielding the effective spectroscopic parameters of the Watson S-reduced Hamiltonian. Examples of the strikingly simple perpendicular spectrum of this nearly symmetric prolate rotor are presented.     

High resolution Fourier transform infrared spectroscopy on CH2DI and CHD2I: evaluation of the ground state constants and analyses of the C-I stretching bands ν3

Abstract

The high resolution (0.0010cm^?1) Fourier transform infrared spectra of the partially deuterated methyl iodide molecules CH₂DI and CHD₂1 have been recorded and analysed in the ν₃ band regions around 510cm^?1. The fundamental band ν₃ is associated with the stretching of the C-I bond and the spectra appear therefore as an asymmetric rotor hybrid a/b-type band and hybrid a/c-type band for CH₂DI and CHD₂I, respectively. About 4700 transitions in the case of CH₂DI and about 3900 transitions in the case of CHD₂I have been assigned. The ground state rotational constants of CH₂DI and CHD₂I have been obtained using the ground state combination differences calculated from the assigned ν₃ transitions and 16 microwave transitions from literature. The S reduced Watson's Hamiltonian has been used in the calculations. In addition, the upper state parameters describing the v₃=1 vibrational states of these molecules have been determined. The obtained ground state constants as well as the upper state parameters have been compared to the corresponding constants of the symmetric top species CH₃I and CD₃I     

Observation and analysis of the Xe−I collisional-pair photoassociation spectrum

The interpretation of the photoassociation spectrum arising in collisions of Xe and I atoms is refined with allowance for new data concerning the interaction potential of Xe and I collisional pairs. Spectroscopic constants for the XeI(B) state are determined:R′ _e =3.264961 Å,D′ _e =33,289.05 cm^?1,w′ _e =113.867826 cm^?1, andw′ _e x′ _e =0.238304 cm^?1.     

The sub-millimeter and Fourier transform microwave spectrum of HZnCl (X Σ)

The pure rotational spectrum of HZnCl (X ¹Σ⁺) has been recorded using sub-millimeter direct-absorption methods in the range of 439-540 GHz and Fourier transform microwave (FTMW) techniques from 9 to 39 GHz. This species was produced by the reaction of zinc vapor and chlorine gas with H₂ or D₂ in a d.c. glow discharge for the sub-millimeter studies. In the FTMW measurements, HZnCl was created in a discharge nozzle from Cl₂ and (CH₃)₂Zn. Between 5 and 10 rotational transitions were measured in the sub-millimeter regime for four zinc and two chlorine isotopologues; four transitions were recorded with the FTMW machine for the main isotopologue, each consisting of several chlorine hyperfine components. The data are consistent with a linear molecule and a ¹Σ⁺ ground electronic state. Rotational and chlorine quadrupole constants were established from the spectra, as well as an r_m⁽²⁾ structure. The Zn-Cl and Zn-H bond lengths were determined to be 2.0829 and 1.5050 Å, respectively; in contrast, the Zn-Cl bond distance in ZnCl is 2.1300 Å, longer by ∼0.050 Å. The zinc-chlorine bond distance therefore shortens with the addition of the H atom. The ³⁵Cl electric quadrupole coupling constant of eQq = −27.429 MHz found for HZnCl suggests that this molecule is primarily an ionic species with some covalent character for the Zn-Cl bond.     

The high-resolution spectrum of the ν1 + ν2 band of NO2: A spin-induced perturbation in the ground state

The spectrum of the ν₁ + ν₂ band of NO₂ has been studied with a resolution of 0.025 cm⁻¹. Spin-rotation constants and rotational constants are reported. An interesting perturbation has been found in the ground state of the molecule which occurs when the K_a = 0 and K_a = 2 levels become accidentally nearly degenerate around N = 42. An explanation of this interaction is presented.     

Light-front quark model and analysis of the spectrum of photons from inclusive B → X s γ decays

The electroweak-decay width Γ(B → X _s γ) is investigated in a light-front (LF) constituent quark model. A new partonlike formula is derived that establishes a simple relation between Γ(B → X _s γ) and the b → sγ decay width. A treatment of the b quark as an on-mass-shell particle and the inclusion of effects that arise from the transverse motion of the b quark in the B meson are basic features of this approach. Adopting different b-quark LF distribution functions, both phenomenological ones and those that are derived from constituent quark models, and neglecting perturbative corrections, we compute the photon energy spectra and the moments of the shape function. It is shown that the LF approach can be matched completely with a heavy-quark expansion (HQE), provided that the constituent b-quark mass is redefined in a way similar to that used in HQE to define the pole mass of the b quark. In this way, the correction to first order in 1/m _b can be eliminated from the total width in agreement with the general statement of HQE. We also show that the photon energy spectra calculated in the LF approach agree well with those obtained in the model of Altarelli et al., provided that the same distribution function is used as an input in both cases. Despite the simplicity of the model, our results are in fairly good agreement both with HQE predictions and with available experimental data.     

High-resolution Fourier transform spectroscopy of the ν2 and ν3 fundamentals of nitrosyl fluoride,FNO

The ν₂ and ν₃ fundamentals of FNO have been recorded with a Fourier transform spectrophotometer at an apodized resolution of approximately 0.004 cm^?1. The Fourier infrared data have been analyzed together with previous microwave data to yield improved molecular parameters for the (000) and (010) vibrational states and the first set of constants for the (001) state. The main results (in cm^?1) are

     

14.

Sub-Doppler laser-Stark and high-resolution Fourier transform spectroscopy of the ν3 band of formic acid     

《Journal of Molecular Spectroscopy》1987,121(2):243-260

The 5.6-μm band of HCOOH, which is the strong carbonyl stretch mode, is analyzed using a combination of sub-Doppler resolution laser-Stark data obtained with a CO laser and Fourier transform data obtained from a Bomem interferometer. The Fourier transform data, including 647 lines with J′ ≤ 22 and K_a ≤ 11, are fit with a Watson-type Hamiltonian to determine excited state constants. The Coriolis interactions with v₅₊₉ and v₆₊₉, previously noted by Kuze et al., are included in the analysis; the former by using an exact diagonalization technique, the latter via perturbation theory. Taking the molecular parameters from this fit, the laser-Stark data are then analyzed to give ground and excited state dipole moments, yielding the following results in Debyes: μ″_a=1.4071(8)μ″_b=0.227(10)μ′_a=1.4353(9)μ′_b=0.214(9), where the errors are 3σ estimates. The laser-Stark data are limited to J′ ≤ 7 and give a ± 14 MHz fit to 191 lines.     

15.

Lifetimes of rovibrational levels of the long-range I′ 1Πg state of H2 and D2: experiment and theory     

Stephen C. Ross  Jun Ando  Koichi Tsukiyama 《Molecular physics》2013,111(2):109-117

The lifetimes of the lowest lying rovibrational levels of the outer well I′ ¹Π_g state of molecular hydrogen were measured for both H₂ and D₂. The measurements were made by direct observation of the time-dependent decay of the fluorescence. The observed lifetimes depend on isotopomer and increase with vibrational excitation. The predominant decay route for these levels is fluorescence. Previously published ab initio lifetimes calculated for these states, which accounted for non-adiabatic interactions [J. Chem. Phys. 92, 7461 (1990)], are in good agreement with experiment for H₂ but are too long by four or five orders of magnitude for D₂. We present new ab initio results at the adiabatic level for the fluorescence lifetimes. The current results are in reasonable agreement with the experimental lifetimes for both H₂ and D₂. We explain the isotopomer and vibrational dependence of the lifetimes and discuss the neglected interactions and decay pathways.     

16.

Observation of the decay Ks → 2γ and measurement of the decay rates KL → 2γ and KS → 2γ     

《Physics letters. [Part B]》1987,199(1):139-146

The decay rates of K_L → 2γ and K_S → 2γ have been measured at the CERN SPS. The results are Γ(K_L→2γ)/χ(K_L→2π₀)=0.632±0.004±0.008 and Γ(K_S→2γ)/Γ(K_L→2γ)=2.3 ±1.0±0.4. This is the first observation of K_S→2γ decays.     

17.

Infrared spectrum and fourier transform spectroscopy of the 2ν1 band of OCSe: Synthesized by using a heat pipe reactor     

《Journal of Molecular Spectroscopy》1987,124(1):46-52

In order to observe the infrared spectrum of OCSe, a sufficient amount was readily synthesized by using a heat pipe reactor. Thirteen vibrational bands were observed in the region of 400 ∼ 4000 cm⁻¹, seven of which have never been reported. The high-resolution FTIR spectrum of the 2ν₁ band of OCSe was recorded with a resolution of 0.005 cm⁻¹. Analysis provided molecular constants for the 2ν₁ band of ¹⁶O¹²C⁸⁰Se and ¹⁶O¹²C⁷⁸Se in natural abundance.     

18.

Millimetre-wave and Fourier transform infrared spectra between 325 cm−1 and 4720 cm−1 of BrCN and global rovibrational analysis of the main isotopomers     

A. FAYT  J. DEMAISON  G. WLODARCZAK  H. BÜRGER 《Molecular physics》2013,111(4-5):675-695

The infrared absorption spectrum of BrCN has been recorded in the re?ion 325–4720 cm^?1 with a Bruker 120 HR interferometer. More than 30 000 lines have been measured and most of them have been assigned: 10734 lines for 151 bands and 10993 lines for 150 bands of ⁷⁹Br¹²C¹⁴N and ⁸¹Br¹²C¹⁴N, respectively. Also new millimetre-wave spectra were measured for the vibrational excited states lying between 1000 cm^?1 and 1400 cm-′. After a band by band analysis of these transitions, rovibrational global analyses have been performed for both isotopomers using all available experimental data. The rotational I-type resonance and the anharmonic resonance associated with k_l22 are taken into account in one-step diagonalization procedures. Sets of 73 molecular parameters are obtained for both isotopomers. It is shown that the existing equilibrium structure is likely to be reliable. The vibrational dependence of the quartic centrifugal distortion constant is analysed for the linear triatomic molecules studied so far.     

19.

An analysis of the F′(0u+) ion-pair state of I2 by optical-optical double resonance     

《Journal of Molecular Spectroscopy》1986,117(1):89-101

     

20.

A theoretical method based on Fourier spectrum analysis for the focusing performances of the X-ray compound refractive lenses   总被引：1，自引：0，他引：1  

叶坚  乐孜纯  梁静秋  刘恺  全必胜  覃亚丽  朱广信 《中国光学快报(英文版)》2004,(6)

It is important to predict the intensity distribution in focusing plane for designing the X-ray compound refractive lenses. On the basis of analyzing the structure of X-ray compound lenses and comparing it with Praunhofer diffraction system, it is concluded that the X-ray focusing system can be regarded as a kind of Praunhofer diffraction system. Therefore, a method based on Fourier spectrum analysis is presented to predict the intensity distribution in the focusing plane for the X-ray lenses. A brief analysis on the relationship between the parameters of X-ray lenses and their focusing performance is also given in this paper.     

	Ground state	$\text{ν}{}_2$	$\text{ν}{}_3$
A	3.1751882 (17)	3.1861249 (12)	3.1958722 (15)
B	0.39508266 (12)	0.39407878 (14)	0.39211484 (14)
C	0.35051504 (11)	0.34899779 (16)	0.34747411 (14)
$\text{ν}{}_0$	0	765.3551 (4)	519.5980 (4)

Sub-Doppler laser-Stark and high-resolution Fourier transform spectroscopy of the ν3 band of formic acid

The 5.6-μm band of HCOOH, which is the strong carbonyl stretch mode, is analyzed using a combination of sub-Doppler resolution laser-Stark data obtained with a CO laser and Fourier transform data obtained from a Bomem interferometer. The Fourier transform data, including 647 lines with J′ ≤ 22 and K_a ≤ 11, are fit with a Watson-type Hamiltonian to determine excited state constants. The Coriolis interactions with v₅₊₉ and v₆₊₉, previously noted by Kuze et al., are included in the analysis; the former by using an exact diagonalization technique, the latter via perturbation theory. Taking the molecular parameters from this fit, the laser-Stark data are then analyzed to give ground and excited state dipole moments, yielding the following results in Debyes: μ″_a=1.4071(8)μ″_b=0.227(10)μ′_a=1.4353(9)μ′_b=0.214(9), where the errors are 3σ estimates. The laser-Stark data are limited to J′ ≤ 7 and give a ± 14 MHz fit to 191 lines.     

Lifetimes of rovibrational levels of the long-range I′ 1Πg state of H2 and D2: experiment and theory

The lifetimes of the lowest lying rovibrational levels of the outer well I′ ¹Π_g state of molecular hydrogen were measured for both H₂ and D₂. The measurements were made by direct observation of the time-dependent decay of the fluorescence. The observed lifetimes depend on isotopomer and increase with vibrational excitation. The predominant decay route for these levels is fluorescence. Previously published ab initio lifetimes calculated for these states, which accounted for non-adiabatic interactions [J. Chem. Phys. 92, 7461 (1990)], are in good agreement with experiment for H₂ but are too long by four or five orders of magnitude for D₂. We present new ab initio results at the adiabatic level for the fluorescence lifetimes. The current results are in reasonable agreement with the experimental lifetimes for both H₂ and D₂. We explain the isotopomer and vibrational dependence of the lifetimes and discuss the neglected interactions and decay pathways.     

Observation of the decay Ks → 2γ and measurement of the decay rates KL → 2γ and KS → 2γ

The decay rates of K_L → 2γ and K_S → 2γ have been measured at the CERN SPS. The results are Γ(K_L→2γ)/χ(K_L→2π₀)=0.632±0.004±0.008 and Γ(K_S→2γ)/Γ(K_L→2γ)=2.3 ±1.0±0.4. This is the first observation of K_S→2γ decays.     

Infrared spectrum and fourier transform spectroscopy of the 2ν1 band of OCSe: Synthesized by using a heat pipe reactor

In order to observe the infrared spectrum of OCSe, a sufficient amount was readily synthesized by using a heat pipe reactor. Thirteen vibrational bands were observed in the region of 400 ∼ 4000 cm⁻¹, seven of which have never been reported. The high-resolution FTIR spectrum of the 2ν₁ band of OCSe was recorded with a resolution of 0.005 cm⁻¹. Analysis provided molecular constants for the 2ν₁ band of ¹⁶O¹²C⁸⁰Se and ¹⁶O¹²C⁷⁸Se in natural abundance.     

Millimetre-wave and Fourier transform infrared spectra between 325 cm−1 and 4720 cm−1 of BrCN and global rovibrational analysis of the main isotopomers

The infrared absorption spectrum of BrCN has been recorded in the re?ion 325–4720 cm^?1 with a Bruker 120 HR interferometer. More than 30 000 lines have been measured and most of them have been assigned: 10734 lines for 151 bands and 10993 lines for 150 bands of ⁷⁹Br¹²C¹⁴N and ⁸¹Br¹²C¹⁴N, respectively. Also new millimetre-wave spectra were measured for the vibrational excited states lying between 1000 cm^?1 and 1400 cm-′. After a band by band analysis of these transitions, rovibrational global analyses have been performed for both isotopomers using all available experimental data. The rotational I-type resonance and the anharmonic resonance associated with k_l22 are taken into account in one-step diagonalization procedures. Sets of 73 molecular parameters are obtained for both isotopomers. It is shown that the existing equilibrium structure is likely to be reliable. The vibrational dependence of the quartic centrifugal distortion constant is analysed for the linear triatomic molecules studied so far.     

A theoretical method based on Fourier spectrum analysis for the focusing performances of the X-ray compound refractive lenses

It is important to predict the intensity distribution in focusing plane for designing the X-ray compound refractive lenses. On the basis of analyzing the structure of X-ray compound lenses and comparing it with Praunhofer diffraction system, it is concluded that the X-ray focusing system can be regarded as a kind of Praunhofer diffraction system. Therefore, a method based on Fourier spectrum analysis is presented to predict the intensity distribution in the focusing plane for the X-ray lenses. A brief analysis on the relationship between the parameters of X-ray lenses and their focusing performance is also given in this paper.