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.     

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.     

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.     

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 KRb (2)(3)Sigma(+) Electronic State

High-resolution spectra of the (3)(1)Pi --> (2)(3)Sigma(+) system of the KRb molecule, obtained after excitation with fixed frequencies Ar(+) laser lines, were recorded on a Connes-type Fourier transform interferometer. Molecular constants of the first 14 vibrational levels of the (2)(3)Sigma(+) state are determined. The RKR potential energy curve is derived. The main spectroscopic constants for this triplet electronic state of the (39)K (85)Rb isotopic species are T(e) = 13 507.146(2) cm(-1), omega(e) = 48.6385(6) cm(-1), B(e) = 0.0254152(5) cm(-1), gamma = 0.00164(4) cm(-1), epsilon = -0.469(2) cm(-1), R(e) = 4.98345 ?, 𝒟(e) = 3447 cm(-1). Copyright 2000 Academic Press.     

The Rotational Analysis of the A(2)Pi(r)-X(2)Sigma(+) Band System of MgBr

The A(2)Pi(r)-X(2)Sigma(+) emission spectrum of the magnesium monobromide radical, MgBr, has been recorded with a Fourier transform spectrometer modified to record double-sided interferograms. The emission spectra of the Deltav = -2, -1, 0, +1 bands were generated in a microwave discharge of a mixture of argon and vaporized MgBr(2). The Deltav = 0 and -1 bands were rotationally resolved, but the F(2) spin component (A(2)Pi(3/2)) in the (1, 1), (1, 2) and vibrational bands with v' > 1 were missing in our spectra because of a strong predissociation in the A state. The molecular constants in both electronic states were determined for the two bromine isotopomers. The r(0) bond length in the A state is about 2.327 ?, which is about 0.02 ? shorter than in the ground state. Franck-Condon factors were calculated from the Rydberg-Klein-Rees potentials, and they reproduce the observed relative intensities of the bandheads. An upper limit for the dissociation energy (D(0)(0)) was obtained as 26 268.4 cm(-1), based on the absence of the energy level with v = 1, A(2)Pi(3/2), J = 1.5 in our spectrum. Copyright 2000 Academic Press.     

Far-Infrared Laser Magnetic Resonance Spectroscopic Study of the nu(2) Bending Fundamental of the CCN Radical in Its &Xtilde;(2)Pi(r) State

Bending vibration-rotation transitions between the (010) μ(2)Sigma(-) and (000) (2)Pi(r) vibronic states of the CCN radical in its ground electronic state have been observed using far-infrared laser magnetic resonance (FIR LMR) spectroscopy. Thirteen FIR laser lines were used to record 769 resonances. The LMR data, combined with previous data, were used to determine vibrational, Renner-Teller, fine-structure, rotational, hyperfine, and molecular g-factor parameters using a least-squares fitting routine. The model used was an N(2) effective Hamiltonian modified to include the Renner-Teller effect explicitly in a (2)Pi electronic state. The band origin for the (010) μ(2)Sigma(-) <-- (000) &Xtilde;(2)Pi(r) transition was determined to be 179.598176 +/- 0.000067 cm(-1). The spin-orbit splitting in the ground state was refined and the complete set of (14)N-hyperfine parameters determined for the first time.     

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   

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.     

Microwave Spectroscopic Study of NiF in the Electronic Ground and Lowest Excited States

The rotational spectra of NiF in the electronic ground (2)Pi state and the lowest electronically excited (2)Sigma state have been observed. The source of nickel atom was sputtering from a nickel electrode or nickel powder placed on a stainless steel electrode. The molecular constants have been determined by a least-squares analysis of the observed transition frequencies. The rapid increase in the Lambda-type splittings in the ground state reveals that the observed rotational transitions are ascribed to the spin substate (2)Pi(3/2). The rotational transitions corresponding to the other substate,(2)Pi(1/2), have not been observed. The large spin-rotation interaction constant gamma in the electronically excited (2)Sigma state is consistent with that from the electronic spectroscopy. Copyright 2001 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.     

The (1)(3)Pi Electronic State of LaF

Rotational studies of bands of the infrared systems (1)(3)Pi-->(1)(3)Delta and (1)(3)Pi(1)-->X(1)Sigma(+) of lanthanum monofluoride were carried out with the aim of characterizing the (1)(3)Pi state, assuming the previous representations of X(1)Sigma(+) and (1)(3)Delta (1-3). The vibrational levels of (1)(3)Pi involved in the analyzed transitions were v=0, 1, 2 of the Omega=0 component, v=0, 1 of the Omega=1 component, and v=0 of the Omega=2 component. Perturbations were observed in both systems which were ascribed to spin-uncoupling interactions between (1)(3)Pi(2)(v=0) and (1)(3)Pi(1)(v=1) levels. A 9x9 matrix representation at equilibrium of the complex of interacting levels (v=0, 1, 2) was constructed, each diagonal v-block corresponding to a triplet model of the rovibrational (3)Pi Hamiltonian. The wavenumbers of some 1910 lines in the two systems were simultaneously fitted (rms error of the fit of about 0.0053 cm(-1)), thus yielding a consistent set of accurate spectroscopic constants for the (1)(3)Pi state; the spin-uncoupling interaction parameter was determined as B(Pi)(0, 1)=0.010917(13) cm(-1). Copyright 2001 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.     

Experimental and Theoretical Study of the Electronic States and Spectra of TeH and TeLi

Gas-phase emission spectra of the hitherto unknown free radical TeLi have been measured in the NIR range with a Fourier-transform spectrometer. The emissions were observed from a fast flow system in which tellurium vapor in argon carrier gas was passed through a microwave discharge and mixed with lithium vapor in an observation tube. Two systems of blue-degraded bands were measured at high spectral resolution in the ranges 8000-9000 and 5700-6700 cm(-1) and vibrational and rotational analyses were performed. In order to aid in the analysis of the experimental data, a series of relativistic configuration interaction calculations has been carried out to obtain potential curves for the low-lying states of TeLi and the isovalent TeH and also electric dipole transition moments connecting them. As in the TeH system, the ground state of TeLi is found to be X(2)Pi(i), but with a remarkably smaller spin-orbit splitting. The TeLi calculations indicate a strongly bound A(2)Sigma(+) state, while in TeH the analogous state is computed to lie significantly higher at approximately 32 000 cm(-1), and it is strongly predissociated. Based on the theoretical analysis, the observed TeLi band systems are assigned to the transitions A(2)Sigma(+)(A1/2)-->X(1)(2)Pi(3/2)(X(1)3/2) and A(2)Sigma(+)(A1/2)-->X(2)(2)Pi(1/2)(X(2)1/2). Analysis of the spectra has yielded the molecular constants (in cm(-1)) X(1)(2)Pi(3/2):omega(e)=457.49(3), omega(e)x(e)=2.482(9), B(0)=0.408908(8); X(2)(2)Pi(1/2): T(e)=2353.44(3), omega(e)=456.28(4), omega(e)x(e)=2.635(8), B(0)=0.414954(8), p(0)=1.00637(4); A(2)Sigma(+): T(e)=8574.64(2), omega(e)=437.81(3), omega(e)x(e)=2.581(8), B(0)=0.423903(8), p(0)=-0.19915(2), where the numbers in parentheses are the standard deviations of the parameters. Comparison of the isovalent TeLi and TeH systems emphasizes that the difference in bonding character (ionic in TeLi vs covalent in TeH) is responsible for qualitative differences in the electronic spectra of these two molecules. Copyright 2001 Academic Press.     

The Rotational Spectrum of SO(2) and the Determination of the Hyperfine Constants and Nuclear Magnetic Shielding Tensors of (33)SO(2) and SO(17)O

Rotational analyses of the B(2)Sigma(+)(u) --> X(2)Sigma(+)(g) system of the (14)N(+)(2) molecule have been extended to include the vibrational levels up to v' = 4. Spectral data from 20 bands obtained from high-resolution Fourier transform spectrometry of a hollow-cathode and a Pointolite lamp were included in the analysis. A global deperturbation yielded molecular parameters of the highly perturbed B(2)Sigma state and interaction parameters A(2)Pi(u) approximately B(2)Sigma(u) with a standard deviation of 0.011 cm(-1). Rotational term values of the B(2)Sigma(+) state were also determined. New perturbations in the B(2)Sigma(+) (v = 0) level have been observed at N approximately 85 and N approximately 96. Copyright 2000 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.     

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.     

Characterization of the Ground State of Br(2) by Laser-Induced Fluorescence Fourier Transform Spectroscopy of the B(3)Pi(0(+))(u)-X(1)Sigma(+)(g) System

The laser-induced fluorescence (LIF) spectrum of the B(3)Pi(0(+))(u)-X(1)Sigma(+)(g) system of Br(2) was recorded by Fourier transform spectroscopy (FTS). The LIF spectra were obtained by using continuous-wave dye laser excitation in the spectral region 16 800-18 000 cm(-1). About 1800 rotationally resolved lines were recorded in 96 fluorescence progressions, originating from the 10 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.