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.     

High-Resolution Study of the BaI A(2)Pi Electronic State

Near-infrared and visible spectra of the A(2)Pi-X(2)Sigma(+), C(2)Pi(1/2)-A(2)Pi(1/2), C(2)Pi(1/2)-B(2)Sigma(+), and C(2)Pi(1/2)-X(2)Sigma(+) band systems of the BaI molecule were recorded by using Fourier transform spectroscopy (FTS). The spectra were produced from the chemiluminescent reaction Ba + I(2) and also by using laser-induced fluorescence (LIF) technique in which the laser sources were a Ti:sapphire single-mode laser, a dye single-mode laser, and a Kr(+) multimode ion laser. Resolved rotational data, originating from 19 vibrational levels (0 相似文献   

Electronic Spectrum of the Antimony Monoxide Radical

The 0-1 band (4271.3 ?) of the B(2)Sigma(+)-X(2)(2)Pi(3/2) transition, the 0-6 band (4275 ?) of the H(2)Pi(3/2)-X(2)(2)Pi(3/2) transition, the 0-0 band (3776.2 ?) of the B(2)Sigma(+)-X(1)(2)Pi(1/2) transition, and the 2-0 (3251.3 ?) as well as the 3-0 (3194.2 ?) bands of the C(2)Sigma(-)-X(1)(2)Pi(1/2) transition of SbO have been photographed at high resolution using the single isotope of antimony (121)Sb. An unambiguous analysis of the rotational structure of all these bands has been carried out for the first time. The magnitude and sign of the Lambda doubling constant p(0) of the X(1)(2)Pi(1/2) state have been determined and as a result of that, the symmetry of the C state has been uniquely identified as C(2)Sigma(-). Accurate rotational constants of all the states involved have been determined by a global linear least-squares fit. Copyright 2000 Academic Press.     

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.     

Fourier Transform Emission Spectroscopy of CuCl

The electronic spectra of CuCl were observed in the 18 000 cm(-1) to 25 000 cm(-1) spectral region using a Bruker IFS 120 HR Fourier transform spectrometer (FTS) and with the FTS associated with the McMath-Pierce Solar Telescope at Kitt Peak. On the basis of ab initio calculations, the labels for the electronic states were revised, and the a(3)Sigma(+)(1)-X(1)Sigma(+) 0-0 band, the b(3)Pi(0)-X(1)Sigma(+) 0-0, 1-0, and 0-1 bands, the b(3)Pi(1)-X(1)Sigma(+) 0-0, 1-0, and 0-1 bands, the A(1)Pi-X(1)Sigma(+) 0-0, 1-0, and 0-2 bands, and the B(1)Sigma(+)-X(1)Sigma(+) 0-0 and 1-0 bands were measured. Improved spectroscopic constants were obtained for the excited and ground states. Copyright 2001 Academic Press.     

First Observation of the Forbidden k-X Transition of (13)C(16)O

A weak rotationally resolved absorption band of (13)C(16)O has been identified from photographic spectra at 1078 ? and assigned to the forbidden transition from the X(1)Sigma(+) (v = 0) ground state to the k(3)Pi (v = 3) valence state. It is similar in structure to the corresponding band of (12)C(16)O but due to the fact it was photographed at a relatively low pressure only the two strongest rotational branches could be positively identified. It is the first time that the forbidden k-X transition has been observed for (13)C(16)O. The measured isotopic shift in the band origin provides independent confirmation of the new vibrational assignment of the k state by G. Berden, R. T. Jongma, D. Van der Zande, and G. Meijer (J. Chem. Phys. 107, 8303-8310 (1997)). Copyright 2000 Academic Press.     

Fourier Transform Emission Spectroscopy of the Low-Lying Electronic States of NbN

The high-resolution spectrum of NbN has been investigated in emission in the 3000-15 000 cm(-1) region using a Fourier transform spectrometer. The bands were excited in a microwave discharge through a mixture of NbCl(5) vapor, approximately 5 mTorr of N(2), and 3 Torr of He. Numerous bands observed in the near-infrared region have been classified into the following transitions: f(1)Phi-c(1)Gamma, e(1)Pi-a(1)Delta, C(3)Pi(0+)-A(3)Sigma(-)(1), C(3)Pi(0-)-A(3)Sigma(-)(1), C(3)Pi(1)-a(1)Delta, C(3)Pi(1)-A(3)Sigma(-)(0), d(1)Sigma(+)-A(3)Sigma(-)(0), and d(1)Sigma(+)-b(1)Sigma(+). These observations are consistent with the energy level diagram provided by laser excitation and emission spectroscopy [Y. Azuma, G. Huang, M. P. J. Lyne, A. J. Merer, and V. I. Srdanov, J. Chem. Phys. 100, 4138-4155 (1993)]. The missing d(1)Sigma(+) state has been observed for the first time and its spectroscopic parameters are consistent with the theoretical predictions of S. R. Langhoff and W. Bauschlicher, Jr. [J. Mol. Spectrosc. 143, 169-179 (1990)]. Rotational analysis of a number of bands has been obtained and improved spectroscopic parameters have been extracted for the low-lying electronic states. The observation of several vibrational bands with v = 1 has enabled us to determine the vibrational intervals and equilibrium bond lengths for the A(3)Sigma(-)(0), a(1)Delta, b(1)Sigma(+), d(1)Sigma(+), and C(3)Pi(1) states. Copyright 2000 Academic Press.     

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.     

Improvement of the Spectroscopic Constants of the PF(A(3)Pi) State and Assignment of the PF(A-X) Transition Dipole Function

High-resolution laser-excitation spectra were acquired for the v'=3-7 levels of the PF(A(3)Pi(0,1,2)<--X(3)Sigma(-)) transition from PF(X(3)Sigma(-)) molecules generated in a discharge flow reactor. These results were combined with lower resolution excitation spectra for the v'=8-11 levels and with existing high-resolution data in the literature for v'=0 and 1 to assign improved spectroscopic constants for PF(A(3)Pi(0,1,2)). The abnormal vibrational energy level spacings for all spin components of the PF(A(3)Pi) state are evidence for a homogeneous interaction with another (3)Pi state. The Lambda-doublet separation in the PF((3)Pi(0)) substate increases with vibrational level, which is taken as evidence for interaction with the PF(b(1)Sigma(+)) state. Laser-induced fluorescence spectra from individual v'=0-5 levels were used to obtain vibrational band intensities of the A-X transition. The strong dependence of the transition dipole on the r-centroid is consistent with the reduction in the radiative lifetimes with increasing v' level. The similarity between the isovalent PF(A(3)Pi) and SO(A(3)Pi) states is noted and the bond dissociation energy of PF(X(3)Sigma(-)) is discussed. Copyright 2001 Academic Press.     

Laser-Induced Fluorescence and Fourier Transform Spectroscopy of NiCl: Identification of a Low-Lying (2)Sigma(+) State (1768 cm(-1))

From a comparison with the spectrum of NiF, a low-lying (2)Sigma(+) state is expected to lie in the first 2000 cm(-1) above the ground X(2)Pi(3/2) state of NiCl. The identification of this (2)Sigma(+) (v = 0) state (at 1768 cm(-1)) has been carried out through the analysis of two electronic transitions (2)Pi(3/2)-(2)Sigma(+) (22 720 cm(-1)) and (2)Pi(1/2)-(2)Sigma(+) (23 210 cm(-1)) recorded by high-resolution Fourier transform spectroscopy. Dispersed fluorescence spectroscopy allowed these transitions to be located on an absolute energy-level diagram that includes the previously studied electronic states. 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 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.     

High-Resolution Fourier Transform Emission Spectroscopy of the B(2)Sigma(+) (v = 0)-X(2)Sigma(+) (v = 0) Transition of the PN(+) Ion

Ultraviolet emission spectrum of the B(2)Sigma(+) (v = 0)-X(2)Sigma(+) (v = 0) transition of the PN(+) ion has been observed at a resolution of 0.05 cm(-1) by a Fourier transform spectrometer. The rotational analysis led to a great improvement of rotational constants in the B(2)Sigma(+) (v = 0) and X(2)Sigma(+) (v = 0) states as well as to the first determination of centrifugal distortion constants for both levels and spin-rotation interaction constant in the X(2)Sigma(+) (v = 0) state. Rotational perturbation in the B(2)Sigma(+) (v = 0) state was observed. Copyright 2000 Academic Press.     

The E(2)Sigma(+) --> C(2)Pi Transition of NO and Term Values for the A, D, E, and C Lowest Rydberg Levels

The E(2)Sigma(+) --> C(2)Pi Rydberg-Rydberg transition of (14)N(16)O near 8492 cm(-1) has been studied by Fourier transform spectrometry in the emission from a dc excited supersonic jet expansion and from a dc discharge under equilibrium conditions. The same transition has also been observed in laser-induced stimulated emission. Line wavenumbers of the 0-0, 1-1, and 2-2 bands, together with data for previously published near-infrared transitions, have been reduced to consistent sets of rovibronic term values for v = 0, 1, and 2 of the A(2)Sigma(+), D(2)Sigma(+), E(2)Sigma(+), and C(2)Pi states which frequently serve as intermediates in the multiphoton excitation of higher Rydberg levels of NO. Copyright 2000 Academic Press.     

Variational Calculations of Rovibrational Energies for CO(2)

In this work, the BaI D(2)Sigma(+) and G(2)Sigma(+) electronic states were investigated using laser-induced fluorescence (LIF) and Fourier transform spectroscopy (FTS). The LIF visible spectra were obtained by using the second harmonic of the Ti:sapphire single-mode laser and the Ar(+) and Kr(+) multimode lasers as excitation sources. Previously recorded data, taken from C. A. Leach, A. A. Tsekouras, and R. N. Zare (1992, J. Mol. Spectrosc. 153, 59-72) and from R. F. Gutterres, J. Vergès, and C. Amiot (1999, J. Mol. Spectrosc. 196, 29-44; 2000, J. Mol. Spectrosc. 200, 253-260; and 2000, J. Mol. Spectrosc. 201, 326-327) were combined with the present data. Accurate and improved molecular constants for the X(2)Sigma(+), B(2)Sigma(+), A('2)Delta, A(2)Pi, C(2)Pi, and D(2)Sigma(+) states and 16 term values of the G(2)Sigma(+) state were derived from a simultaneous treatment of the whole data set (12 684 transitions) with a standard deviation of 3.26x10(-3) cm(-1). Copyright 2001 Academic Press.     

Optical Spectroscopy of Diatomic Species: Copper with Group 14 Elements (Si, Ge, Sn, Pb)

Electronic band systems of the gaseous diatomic compounds of copper and various X elements of the 14th column (Si, Ge, Sn, Pb) have been observed by thermal excitation in the red part of the visible spectrum. Vibrational analysis of the two subsystems observed for each of these molecules (except for CuPb with only one system) are reported and assigned as (2)Sigma(+)-(2)Pi(3/2) and (2)Sigma(+)-(2)Pi(1/2) transitions. The variation of the spin-orbit splitting of the (2)Pi lower states from CuSi to CuSn follows closely that of the np shell spin-orbit parameters in the group 14 atoms. This fully corroborates previous ab initio calculations that predict a (2)Pi(r) ground state with the ionic Cu(+) (3d(10))X(-)(pvarsigma(2)ppi) configuration for these molecules. Copyright 2000 Academic Press.     

Submillimeter-Wave Spectroscopy of CO in the a(3)Pi State

Submillimeter-wave absorption spectrum of CO in electronically excited a(3)Pi state was observed in the 540-830 GHz region by using a phase-locked BWO spectrometer. New rotational transitions up to J = 9-8 in the vibrational excited states up to v = 5 were analyzed accompanied with previous observations in the RF and millimeter-wave regions. A multivibrational states fit among a' (3)Sigma(+) (v = 0-3) and a(3)Pi (v = 0-7) states was performed in order to analyze overall perturbation between the a(3)Pi and a' (3)Sigma(+) states. As a result, the deperturbed rotational parameters were derived precisely to improve the RKR potential. 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.     

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.     

The Comet-Tail (A(2)Pi(i)-X(2)Sigma(+)) System of (12)C(16)O(+): A Reinvestigation

The emission spectrum of the comet-tail (A(2)Pi(i)-X(2)Sigma(+)) system of (12)C(16)O(+) produced in the cathode glow of a hollow-cathode discharge tube and photographed in the spectral region 3345-8500 ? at high resolution was reinvestigated. Detailed rotational analysis of 10 bands involving 5 vibrational levels v = 0 to 4 of each of the A and X states was carried out. Spin-splitting of the rotational levels was observed for the analyzed bands. The observed intensity distribution of the branches is found to be in good agreement with theoretical calculations. Molecular constants for both the A and X states were obtained from a global fit of the present data of the A-X system and the infrared and microwave data available from the literature for v = 0, 1, 2, 3, and 4 of state X, using effective Hamiltonian for the A(2)Pi state and matrix elements for both A and X states. The present work suggests that the A(2)Pi(i) state changes from Hund's case (a) at low J values to Hund's case (b) at high J values. Copyright 2000 Academic Press.