High-Resolution Laser Spectroscopy of YbCl: The A(2)Pi-X(2)Sigma(+) Transition

The A(2)Pi-X(2)Sigma(+) transition of (174)Yb(35)Cl and (172)Yb(35)Cl has been rotationally analyzed for the first time. Doppler-limited laser excitation spectroscopy with selective detection of fluorescence was used to obtain spectra of the 0-0 and 1-0 bands with a measurement accuracy of approximately 0.0035 cm(-1). Resolved fluorescence was used to record the 0-1, 0-2, and 0-3 bands and to unequivocally assign the rotational numbering, N, to the laser excitation spectra. In total, over 1300 line positions have been measured and assigned for each of the two isotopomers and employed in least-squares fits of molecular parameters. The principal results for the A(2)Pi state are A(e) = 1491.494(2) cm(-1) and R(e) = 2.4433(1) ?, and for the X(2)Sigma(+) state, R(e) = 2.4883(2) ? and gamma(e) = 4.59(2) x 10(-3) cm(-1). The interaction between the X(2)Sigma(+) and A(2)Pi states has been investigated and is shown to be the main contributor to the spin-rotation splitting in the ground state. Copyright 2000 Academic Press.     

The Near-Infrared (3)Phi --> (1)(3)Delta Transition of LaF

Rotational analyses of 32 subbands of the near-infrared (3)Phi --> (1)(3)Delta system of LaF have been carried out, involving the levels v = 0-7 of the two states. The three subsystems were first treated as separate singlet systems, directly at equilibrium. Perturbations were revealed in the lower state, ascribed to spin-uncoupling interactions between (1)(3)Delta(3)(v) and (1)(3)Delta(2)(v + 1) levels. A 21 x 21 matrix representation at equilibrium of the complex of interacting levels (v = 0-6) was then constructed, each diagonal v-block corresponding to a triplet model of the rovibrational (3)Delta Hamiltonian. The observed perturbations were completely reduced in the harmonic oscillator approximation with an experimental value of the interaction parameter B(Delta)(0,1) = 0.01322(2) cm(-1). The wavenumbers of some 4500 lines of the system were fitted with an rms error of about 0.005 cm(-1). (Line lists are available in electronic form via http://www-obs.univ-lyon1.fr/~ABernard/index.html.) Copyright 2000 Academic Press.     

The Near-Infrared Transition of CuCl Observed by Intracavity Laser Spectroscopy

The near-infrared electronic transition of CuCl, occurring in the region of 745 nm, was recorded using intracavity laser absorption spectroscopy. The (0, 0), (1, 1), and (2, 2) vibronic bands were analyzed, and from this the molecular constants for the two electronic states were derived. Originally assigned as A' (3)Sigma(+)-X(1)Sigma(+), we have confirmed that this transition does not connect to the ground state, but occurs between two unknown excited states. The excited CuCl molecules were produced in a copper hollow cathode, operated using argon and a small amount of CCl(4). Line positions were referenced to iodine spectra observed from a heated extracavity cell using the broadband spectral output of the intracavity laser as the light source. Copyright 2000 Academic Press.     

Fourier Transform Spectroscopy of the A'(1)Pi-X(1)Sigma(+) System of CaO

The A'(1)Pi-X(1)Sigma(+) near-infrared system of CaO was observed for the first time at high resolution using a Fourier transform spectrometer. The A'(1)Pi-X(1)Sigma(+) chemiluminescence was excited in a Ca + N(2)O flame produced in a Broida-type oven. More than 3000 rotational lines, classified into 19 bands involving the A'(1)Pi 0 /= 2) levels with the nearby b(3)Sigma(+) (v-2) levels has been detected. An extended set of A'(1)Pi (v = 0-3) data has been obtained which is suitable for use in a future multistate deperturbation analysis of the a(3)Pi approximately A'(1)Pi approximately b(3)Sigma(+) approximately A(1)Sigma(+) complex of excited states. The new near-infrared spectra of the A'(1)Pi-X(1)Sigma(+) transition of CaO also permits the first direct high-resolution linkage between the orange and green systems and the near-infrared bands. Copyright 2000 Academic Press.     

The Electronic Spectrum of Germanium Monosulfide: Rotational Structure in the A(1)Pi-X(1)Sigma(+) Transition in (70)GeS

The emission spectrum of the specific isotopomer (70)GeS was excited in a microwave (2450-MHz) discharge and the A(1)Pi-X(1)Sigma(+) transition (270-430 nm) was photographed under high resolution on a 10.6-m Ebert grating spectrograph. The rotational analysis of 43 bands led to the determination of accurate vibrational and rotational constants. Making use of these constants, the potential energy curves for the A(1)Pi and X(1)Sigma(+) states were generated by the RKR method and Franck-Condon factors and r-centroids were computed for the bands analyzed. The present extensive high-resolution study has revealed only a few localized perturbations in the A(1)Pi (v'=4, 5, 9) vibronic states, which contrasts with the situation in the isovalent molecules such as GeO, SiS, and SiSe. Copyright 2001 Academic Press.     

High-Resolution Laser Photoacoustic Spectroscopy of HSiF(3): The 5nu(1) and 6nu(1) Overtone Bands

A spectrum of HSiF(3) has been recorded at room temperature with a gas pressure of 20-50 Torr in the near-infrared region. A laser photoacoustic spectrometer consisting of a longitudinal resonant cell coupled to a titanium:sapphire ring laser was employed. The 5nu(1) and 6nu(1) overtone bands of H(28)SiF(3) associated with the Si-H stretching have been observed at high resolution (3 x 10(-2) cm(-1)) in the regions 10 900-10 960 and 12 875-12 925 cm(-1), respectively. About 450 lines of the 5nu(1)-0 band have been assigned (J 相似文献   

High-Resolution Laser Spectroscopy of YbCl: The B(2)Sigma(+)-X(2)Sigma(+) Transition

High-resolution laser excitation spectra have been obtained for the 0-0, 1-1, and 0-1 bands of the B(2)Sigma(+)-X(2)Sigma(+) transition of YbCl and a rotational analysis has been performed on the (174)Yb(35)Cl and (172)Yb(35)Cl isotopomers. Comparison of the spin-rotation constant, gamma, for the B(2)Sigma(+) state with the lambda-doubling constant of the A(2)Pi(1/2) state (1) shows that the two excited states form a unique perturber pair arising from the 6psigma and 6ppi orbitals centered on the Yb(+) ion. The principal results for the B(2)Sigma(+) state are B(e)=0.097552(5) cm(-1), R(e)=2.43623(6) ?, gamma(e)=-2.1655(6)x10(-4) cm(-1), and DeltaG(1/2)=313.111(2) cm(-1). Copyright 2001 Academic Press.     

Laser Spectroscopy 1: Basic Principles & Laser Spectroscopy 2: Experimental Techniques (5th edition)

Electron and Ion Spectroscopy of Solids. Edited by L. Fiermans, J. Vennik and W. Dekeyser. (Plenum Publishing Corp., 1978.) [Pp. xi + 475.] $57·00.

Ellipsometry and Polarized Light. By R. M. A. Azzam and M. M. Bashara. (North-Holland, 1977.) [Pp. ix + 529.]

Physical Fluid Dynamics. By D. J. Tritton. (Van Nostrand Reinhold, 1977.) [Pp. xv + 362.] £5·50. Scope: Treatise/textbook. Level: Undergraduate/post graduate.

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Optical Information Processing, Volume 2. Edited by E. S. Barrekete, G. W. Stroke, Y. E. Nesterikhin and W. E. Kock. (Plenum Publishing Corp., 1978.) [Pp. xi + 452.] $45·00. Scope: Seminar Proceedings. Level: Research.

Detection of Optical and Infrared Radiation. By R. H. Kingston. (Springer-Verlag, Berlin, 1978.) [Pp. viii + 140.] DM 43; $21·50. Scope: Monograph. Level: 2nd/3rd Year Undergraduate and Postgraduate.

Optical Shop Testing. Edited by Daniel Malacara. (John Wiley-Interscience, 1978.) [Pp. xix + 523.] £21·15; $38·00. Scope: Practical Manual. Level: Research.

A Practical Introduction to Electronic Circuits. Edited by M. Hartley Jones. (Cambridge University Press, 1978.) [Pp. xii + 237.] £9·50.

Vectors in Three-dimensional Space. By J. S. R. Chisholm. (Cambridge University Press, 1978.) [Pp. xii + 291.] Hardback £15·00; Soft cover £4·95.

Magnetic Field Generation in Electrically Conducting Fluids. By H. K. Moffatt. (Cambridge University Press, 1978.) [Pp. x + 343.] £15·50. Level: Specialist/postgraduate. Scope: Monograph.

Photoelectron Statistics. By B. Salbh. (Springer-Verlag, 1978.) [Pp. xiii + 441.] DM 68; $31·30. Level: Postgraduate and research.

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The Force of Knowledge. The Scientific Dimension of Society. By J. M. Ziman. (Cambridge University Press, 1976-7.) [ix + 437 pp.] £4·75.     

The Ultraviolet Spectrum of the FeF Radical: A Study of the (6)Pi-X(6)Delta and (6)Phi-X(6)Delta Band Systems at 330 and 323 nm Respectively

Two band systems of FeF have been recorded at Doppler-limited linewidths by laser-induced fluorescence. The 330-nm system provided data for three subbands of the (0,0) band of the (6)Pi-X(6)Delta system and showed that levels of the (6)Pi(5/2) and (6)Pi(3/2) components are significantly perturbed. In the 323-nm system, the (0,0) band of the (6)Phi-X(6)Delta system was found to be overlapped by the (1,0) band of the (6)Pi-X(6)Delta system. Data were obtained for three subbands of the (1,0) (6)Pi-X(6)Delta system and for five subbands of the (0, 0) (6)Phi-X(6)Delta system. This work considerably extends the previous study by Pouilly et al. (B. Pouilly, J. Schamps, D. J. W. Lumley, and R. F. Barrow, J. Phys. B 11, 2281-2287 (1978)) because it is a higher resolution study with a lower temperature production of FeF by a continuous flow discharge method. The data recorded were combined with millimeter-wave data for FeF in the X(6)Delta state and fitted with an effective Hamiltonian to determine the major parameters for FeF in the X(6)Delta, (6)Pi, and (6)Phi electronic levels. Copyright 2001 Academic Press.     

Optical-Optical Double Resonance Spectroscopy of the H1(u)((3)P(1))-A(3)Pi(1u)-X(1)Sigma(+)(g) Transition of I(2)

We report the analysis of the H1(u)((3)P(1)) state of I(2) by optical-optical double resonance. This state lies in the second tier of ion-pair states and its observation was achieved by using the (1 + 2) photoexcitation sequence using the A(3)Pi(1u) state as an intermediate. The molecular parameters were obtained from data for 0 相似文献   

A Reinvestigation of the c(3)Pi-X(1)Sigma(+) (0-0) Absorption Band of Carbon Monoxide

The forbidden c(3)Pi-X(1)Sigma(+) (0-0) absorption band of carbon monoxide has been reinvestigated under different pressure conditions using the 10.7-m VUV spectrograph at Meudon. Overlap with the allowed C(1)Pi-X(1)Sigma(+) (0-0) band at lower transition energy has been taken into account. We have identified a new rotational branch corresponding to an S-type branch and extended the analysis to both higher and lower J. An analysis of the band structure and the low J transition lines suggests that the band gains its intensity predominantly as a result of an interaction of the c(3)Pi state with a (1)Sigma(+) state, most likely the C(1)Sigma(+) (v = 0) state. Molecular constants have been obtained for the c(3)Pi state that are in reasonable agreement with those previously published. The apparently anomalous small value for the centrifugal distortion constant is explained by a homogeneous perturbation with the k(3)Pi valence state. Copyright 2000 Academic Press.     

Near-Infrared Spectrum of the A(2)Pi(i)-X(2)Sigma(+) (2,0) Band of CN Studied by Concentration Modulation Laser Spectroscopy

The rotational structure of (2,0) vibrational band of A(2)Pi(i)-X(2)Sigma(+) transition of CN has been studied by concentration-modulation laser spectroscopy using a Ti:sapphire laser. The CN radical was produced in the ac glow discharge of acetonitrile with helium as the carrier gas. All 12 branches including four new branches have been observed and measured with an absolute accuracy of 0.007 cm(-1) in the region 12 450-12 750 cm(-1). Analysis of the spectra has led to improved molecular parameters of the A(2)Pi(i) (v' = 2) state. Copyright 2001 Academic Press.     

牛肉嫩度的近红外光谱法检测技术研究

利用近红外光谱技术研究了牛肉嫩度的检测方法。在波数为4 000～10 000 cm-1范围内测定牛肉样本近红外吸收光谱,然后用沃-布剪切仪测得牛肉样本(背长肌)的最大剪切力值并进行主观嫩度等级评价。把剪切力值小于6 kg的牛肉归为嫩牛肉,等级值定为1;大于9 kg的牛肉归为老牛肉,等级值定为3;介于6和9 kg之间的牛肉归为中等嫩度的牛肉,等级值定为2。研究结果表明,老牛肉吸收的近红外光一般都要比嫩牛肉多,表现为吸光度要大;用多元线性回归法对校正集建立模型,得到相关系数r为0.806;用此模型对牛肉预测集19个样本进行预测,分级正确率为84.21%。该研究说明利用近红外技术对牛肉嫩度进行预测是可行的。     

相关检测技术在近红外光谱分析中的应用

运用信号分析的理论,研究了把相关检测技术应用于近红外光谱分析的方法。通过作药品甲硝唑纯品光谱及混合品光谱的相关函数值,并对相关曲线进行分析,结果表明通过相关处理,光谱信息得到了分离和增强,可以作为一种光谱信息特征提取的有效方法,用于定性和定量分析,对解决近红外光谱检测中光谱叠加、信息率低的难题提供了一种新的思路和探索。     

High-Resolution Laser Spectroscopy of YbCl: The AΠ–XΣ Transition

The A²Π–X²Σ⁺ transition of ¹⁷⁴Yb³⁵Cl and ¹⁷²Yb³⁵Cl has been rotationally analyzed for the first time. Doppler-limited laser excitation spectroscopy with selective detection of fluorescence was used to obtain spectra of the 0–0 and 1–0 bands with a measurement accuracy of approximately 0.0035 cm⁻¹. Resolved fluorescence was used to record the 0–1, 0–2, and 0–3 bands and to unequivocally assign the rotational numbering, N, to the laser excitation spectra. In total, over 1300 line positions have been measured and assigned for each of the two isotopomers and employed in least-squares fits of molecular parameters. The principal results for the A²Π state are A_e = 1491.494(2) cm⁻¹ and R_e = 2.4433(1) Å, and for the X²Σ⁺ state, R_e = 2.4883(2) Å and γ_e = 4.59(2) × 10⁻³ cm⁻¹. The interaction between the X²Σ⁺ and A²Π states has been investigated and is shown to be the main contributor to the spin–rotation splitting in the ground state.     

Anomalous Vibrational Dependence of the Rotational and Hyperfine Parameters in the B(4)Pi-X(4)Sigma(-) Transition of NbO

The laser excitation spectrum of jet-cooled NbO in the region 16 000-18 000 cm(-1) has been recorded at high resolution, giving rotational and hyperfine constants for the levels v=0-3 of the B(4)Pi state and v=1 of the X(4)Sigma(-) state; zero gaps have also been measured at low resolution for some weaker bands involving higher vibrational levels. Taken together with the laser data for the B-X (0,0) band from Adam et al. (J. Chem. Phys. 94, 6240-6262 (1994)) and the Fourier transform emission data for the doublet manifold from Launila et al. (J. Mol. Spectrosc. 186, 131-143 (1997)), the new data give a very complete picture of the vibrational energy level pattern in this region. Strong irregularities in the vibrational dependences of the B(4)Pi rotational and hyperfine constants can be interpreted in terms of spin-orbit interaction between the B(4)Pi state and the f(2)Pi, e(2)Phi, and d(2)Delta states. The interaction is strong enough that all three doublet states can be seen in absorption from the X(4)Sigma(-) ground state, adding to the complexity of the spectrum. The hitherto unknown sigmadeltasigma* (4)Delta state is estimated to lie near 17 500 cm(-1), from the change of sign in the spin-rotation parameter gamma of the B(4)Pi state between v=2 and 3. Copyright 2001 Academic Press.     

Fourier Transform Spectroscopy of Chemiluminescence from the SrO A(1)Sigma(+)-X(1)Sigma(+) Transition

The A(1)Sigma(+)-X(1)Sigma(+) chemiluminescence spectrum of SrO was observed using a Fourier transform spectrometer. SrO was produced in a Broida-type oven from the Sr + N(2)O reaction. A total of 75 bands from (88)SrO, (87)SrO, and (86)SrO were measured in the range of 7600-13 600 cm(-1) at a resolution of 0.04 cm(-1). The vibrational levels of the ground state were observed up to v" = 12 and over 10 000 rovibrational lines with J as high as 153 were analyzed at a precision of about 0.005 cm(-1). Significantly improved spectral constants for the ground state were obtained by representing the perturbed excited state by term values and by adding the known microwave data and infrared data to our fit. Strong perturbations were observed in the upper A state. The vibrational levels of the A(1)Sigma(+) state were measured up to v' = 8 and some new perturbations are reported. Copyright 2000 Academic Press.     

High-Resolution Absorption Spectroscopy of the 3nu(1) and 3nu(1) + nu(3) Bands of Propyne

The 3nu(1) and 3nu(1) + nu(3) bands of propyne have been recorded at Doppler-limited resolution by Fourier transform spectroscopy and intracavity laser absorption spectroscopy, respectively. The two bands show a mostly unperturbed J rotational structure for each individual K subband. However, as a rule the K structure ordering is perturbed in overtone transitions of propyne and different effective parameters associated with each K subband have been determined. From the vibrational energy levels, a value of -6.6 cm(-1) has been obtained for the x(13) cross anharmonicity in perfect agreement with the origins of the nu(1) + nu(3) and 2nu(1) + nu(3) combination bands estimated from the FTIR spectrum. Hot bands from the v(9) = 1 and v(10) = 1 levels associated with the 3nu(1) + nu(3) combination band have been partly rotationally analyzed and the retrieved values of x(39) and x(3,10) are in good agreement with literature values. Finally, the 4nu(1) + nu(9) - nu(9) band centered at 12 636.6 cm(-1) has been recorded by ICLAS. The red shift of this hot band relative to 4nu(1) and the DeltaB(v) value are discussed in relation to the anharmonic interaction between the 4nu(1) and 3nu(1) + nu(3) + nu(5) levels. Copyright 2000 Academic Press.     

Determination of the Electron Density in an Argon Laser Plasma by Spectroscopy of the Hydrogen Hα and Hβ Lines

From measurements of the H_α and H_β spectral line profiles in a plasma, a method is developed which allows to separate the contributions of Doppler and Stark broadening. This method is superior to the deconvolution of Voigt profiles, in particular, when the lines are of low intensity. The electron density in the plasma can be calculated from the Stark broadening. An example is the low pressure (p ≈ 1 hPa) arc discharge of argon ion lasers which is characteristised by electron densities of approximately 10¹⁴ cm^?3 at heavy particle temperatures of about 10⁴ K. These plasma parameters lead to a broadening of the Balmer H_α and H_β spectral lines of hydrogen, which has a low concentration within the discharge area. The spectral lines are broadened due to the electron density dependent Stark effect and the temperature responsive Doppler effect. The results are consistent with predictions of the argon ion laser modelling.