This article provides an overview of recent astronomical studies and a closely coordinated laboratory program devoted to the study of the physics and chemistry of carbon rich Asymptotic Giant Branch (AGB) stars. The increased sensitivity and angular resolution of high altitude ground-based millimeter-wave interferometers in the past few years has enabled molecular astronomers to determine the excitation

Previously unobserved nitrous oxide transitions around 2.5 μm are measured by intracavity laser absorption spectroscopy (ICLAS) analyzed by time-resolved Fourier transform (TRFT) spectrometer. With an accuracy of the order of 10(-3) cm(-1), measured positions of 1637 assigned weak transitions are provided. They belong to 42 vibrational transitions, among which 33 are observed for the first time. These

In a classic paper by G. Herzberg and J. W. C. Johns entitled "The Spectrum and Structure of Singlet CH(2)" (Proc. Roy. Soc. A 295, 107-128 (1966)) the analysis of the &btilde;(1)B(1)<--ã(1)A(1) red absorption band system of CH(2) is discussed in detail for the first time. In addition to that band system the observation of a fragment of a weak near ultraviolet absorption band system is reported. The

In this paper we show that the rotational structure of the nu(5)/2nu(9) infrared band near 11 &mgr;m can be synthesized to high accuracy from pure rotational measurements in the millimeter- and submillimeter-wave region. The analysis uses an internal axis system Hamiltonian that accounts for the rotational dependence of the torsional splitting in 2nu(9), the induced torsional splitting in nu(5), and

The electric dipole moments of symmetric top tertiary butyl derivatives were determined from Stark effect measurements made with cavity Fourier transform microwave spectroscopy under conditions of supersonic expansion. The resulting values are 1.9562(15), 2.1817(16), 2.2574(17) and 2.2122(17) D for tertiary butyl fluoride, chloride, bromide, and iodide, and 4.0129(30), and 4.0640(31) for tertiary butyl

For the first time the 118-GHz line of the oxygen molecule was investigated in the laboratory under a real atmosphere. The experiment was carried out by modern resonator spectroscopy methods on the laboratory air at atmospheric pressure. The shape of the line under the real atmosphere was found to fit the Van Vleck-Weisskopf profile within experimental accuracy. The air broadening parameter value was

The nu(3) band of D(3)SiF near 890 cm(-1) recorded with a resolution of 2.4x10(-3) cm(-1) has been explored for the (29)Si and (30)Si isotopic species. Moreover, the nu(3)+nu(6)-nu(6) and 2nu(3)-nu(3) bands for the main (28)Si isotopomer have been assigned. For this purpose the nu(3)+nu(6) and 2nu(3) bands at 1435.697 and 1769.531 cm(-1) have been studied. Ground state parameters of the (29)Si and

Glyoxylic acid is a possible candidate for interstellar detection. Many transitions of the submillimeter wave spectrum of the ground vibrational state of its most stable conformer have been measured for the first time. These transitions have been used together with microwave transitions measured previously to obtain accurate spectroscopic constants that should facilitate a search for this compound

With a tunable diode-laser spectrometer, absolute line intensity measurements have been made in the spectrum of cyanogen chloride in the vicinity of 710 cm(-1). The intensity of the fundamental nu(1) band has been found to be 6.088 cm(-2) atm(-1) for the (35)ClCN isotopomer and 7.121 cm(-2) atm(-1) for the (37)ClCN form. The influence of the Fermi resonance on the band intensity has been analyzed.

For the first time the half-width within the complex Robert-Bonamy (CRB) formalism is calculated without making the mean relative thermal velocity approximation. The application is to the nitrogen-broadened half-width of the 500.4-GHz transition (34(2 32)<--34(1 33)) of the ground vibrational state of ozone. For each state of the perturber, the optical cross sections are determined at a number of velocities

Using a tunable diode-laser spectrometer, we have measured N(2)-broadening coefficients of 87 individual rovibrational lines in the P and R branches of the nu(3) band of methyl chloride (CH(3)(35)Cl) at 203.2 K. These lines with J values ranging from 2 to 22 and K from 0 to 6 are located in the range 711-751 cm(-1). Most of the collisional widths are obtained by modeling the spectral region from the

For the first time, the emission spectrum of A(3)Pi(0)-X(1)Sigma(+) band system of InCl molecule has been recorded on BOMEM DA8 Fourier transform spectrometer at an apodized resolution of 0.025 cm(-1). The rotational structure of 1-0, 2-1, 0-0, 0-1, 1-2, 0-2, and 1-3 bands belonging to the A(3)Pi(0)-X(1)Sigma(+) transition of In(35)Cl has been analyzed and accurate equilibrium rotational constants

High-resolution infrared spectra of the four isotopomers of FClO(3) of C(3v) symmetry have been analyzed in order to obtain data on overtones of the nu(6) vibrational mode. For v(6)=2, two different approaches have been used. The component with l(6)=0 has been studied by the analysis of the 2nu(6)(0) parallel band at 809 cm(-1) and 779 cm(-1) for the species with (16)O and (18)O respectively. But since

The new laboratory measurements of R. Schermaul et al. (J. Mol. Spectrosc. 208), for the near-infrared and visible spectrum of water vapor, covering the 2nu+delta, 3nu, 3nu+delta, and 4nu polyads, are combined with accurate calculations of weaker lines to provide a new, comprehensive linelist of water transitions for the spectral region 8600-15 000 cm(-1). The resulting ESA-WVR linelist reproduces

New laboratory measurements are presented for the near-infrared and visible spectrum (8600-15 000 cm(-1)) of water vapor. Spectral line parameters, principally intensities and air-broadening coefficients, are derived from Fourier transform spectroscopic measurements at high resolution (0.03 cm(-1)), a range of optical path lengths (5-513 m), and temperatures of both 252 and 296 K. Experimental line

Using a stabilized diode-laser spectrometer, we have studied the line profiles of water vapor near 7185.59 cm(-1). With low pressures of pure gas (

The laser-induced fluorescence excitation spectrum of jet-cooled NiF has been studied in the range 435-570 nm. Eight electronic transitions, involving four high-lying Pi components and two lower states, the ground state X(2)Pi(3/2), and the low-lying state [0.25](2)Sigma, respectively, have been recorded. Two new Pi components are identified for the first time and their rotational constants are determined

The C(2)Pi(r)-->X(2)Sigma(+) electronic transition of BO has been observed in emission under high resolution. Thirty-six bands have been analyzed for (11)BO and six for (10)BO. The C state is shown to be a regular state and better constants are given. Strong perturbations are discussed on the basis of the theoretical calculations of Karna and Grein (J. Mol. Spectrosc. 122, 356-364 (1987)). Copyright

The octad system of methane (12)CH(4) has been analyzed with a fourth-order (459 parameters) Hamiltonian for energy levels and a third-order (28 parameters) dipole moment expansion for infrared intensities. Nearly 8000 assigned positions and 2500 measured line intensities (obtained with the Fourier transform spectrometer located at Kitt Peak National Observatory/National Solar Observatory) have been

Relative intensities in the vibrational structure of the Ã(1)A(u)(C(2h))-&Xtilde;(1)Sigma(+)(g)(D(infinityh)) electronic transition of acetylene are calculated. The calculation takes account of the large change of geometry and the change in the normal coordinates (the Dushinskií effect) between the two states. Because conventional vibrational wavefunctions for a nonlinear state do not behave correctly

The six-dimensional potential energy surface (PES) of the most stable isomer of C(2)N(2) is investigated using the coupled cluster single and double approach with perturbative treatment of triple excitations (CCSD(T)). The full quartic force fields of this molecule and some of its isotopomers are calculated in dimensionless normal coordinates. This quartic force field has been optimized in order to

Three of the four components of the 3nu(1)+3nu(3) tetrad of (12)C(16)O(2) and (13)C(16)O(2), labeled 30031, 30032, and 30033 in HITRAN notation, have been observed by intracavity laser absorption spectroscopy in the 10 450- to 11 000-cm(-1) region. The rotational analysis has yielded the rovibrational parameters of the vibrational states. The experimental values are found to be in very good agreement

Pressure-broadened half-widths and pressure-induced line shifts for the two most important bands of water vapor in the 0.7-&mgr;m region are determined using the complex Robert-Bonamy (CRB) formalism. The calculations are made with nitrogen and oxygen as the perturbing gas from which values for air as the perturbing gas are determined. The intermolecular potential is taken as a sum of electrostatic

The rotational spectrum of the deuterated isopropanol (CH(3))(2)CHOD has been observed by Fourier transform microwave spectroscopy and analyzed to yield tunneling splitting of 4431.4613 (17) MHz, between the antisymmetric and the symmetric gauche forms, which is much larger than the 2400 MHz estimated from the internal-rotation potential function reported in the literature. The potential function for

The 1(01)-0(00), 2(02)-1(01), and 3(03)-2(02) rotational transitions of the FCO radical are observed at 22.3, 44.5, and 66.8 GHz, respectively, using a Fourier transform millimeter-wave spectrometer with a pulsed discharge nozzle. The FCO radical is produced by discharging F(2)CO diluted in the Ar buffer gas. Twelve fine and hyperfine components for the three transitions are observed, and the effective

The equilibrium structure of 1,2,5-oxadiazole has been calculated ab initio at the CCSD(T) level using a polarized valence quadruple zeta basis set. The harmonic force field has also been calculated at the MP2/cc-pVTZ, B3LYP/6-311++G(3df, 2pd), and B3LYP/cc-pVQZ levels. These force fields have been subsequently scaled and further refined by fitting them to the experimental values of the vibrational

A high-resolution analysis of the {nu(2), nu(3)} and {nu(4), nu(6)} bands of the two isotopomers of chloryl fluoride F(35)ClO(2) and F(37)ClO(2) has been carried out for the first time using simultaneously infrared spectra recorded around 16&mgr;m and 26&mgr;m with a resolution of ca. 0.003 cm(-1) and microwave and submillimeter-wave transitions occurring within the vibrational states 2(1), 3(1), 4(1)

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

Pulsed-beam Fourier transform microwave spectroscopy was used to observe and assign the rotational spectra of the argon-ketene van der Waals complex. Tunneling of the hydrogen or deuterium atoms splits the a- and b-type rotational transitions of H(2)CCO-Ar, H(2)(13)CCO-Ar, H(2)C(13)CO-Ar, and D(2)CCO-Ar into two states. This internal motion appears to be quenched for HDCCO-Ar where only one state is

The nu(5) fundamental (C-C stretching) of CH(3)CD(3) shows a resolved torsional structure, caused by perturbations due mainly to the linear dependence of the torsional potential barrier on the normal coordinate Q(5). We were able to analyze this structure and to assign vibration-rotation transition wavenumbers for all five torsional components, classified according to the symmetry species of the G(18)((3))

The Fourier transform infrared (FTIR) spectrum of the nu(12) fundamental band of ethylene-(13)C(2) ((13)C(2)H(4)) was recorded with an unapodized resolution of 0.004 cm(-1) in the frequency range from 1380 to 1500 cm(-1). Rovibrational constants for the upper state (nu(12)=1) up to five quartic and three sextic centrifugal distortion terms were derived for the first time by assigning and fitting a

We present an analysis of the A0(+)(6(3)P(1))-->X0(+)(6(1)S(0)) bound-bound and bound-free fluorescence spectrum, and of the A0(+)(6(3)P(1))<--X0(+)(6(1)S(0)) and B1(6(3)P(1))<--X0(+)(6(1)S(0)) bound-bound excitation spectrum of the HgKr van der Waals molecule. The A-->X fluorescence spectrum, which was observed for the first time, as well as the excitation spectra were recorded using a pulsed supersonic

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

An extensive ab initio molecular orbital study of the (27)Al nuclear spin-rotation and nuclear quadrupolar coupling constants in aluminum hydride, AlH, has been performed. The (27)Al nuclear spin-rotation constant (C( perpendicular)), calculated to be approximately 300 kHz, was neglected in a previous analysis of the hyperfine structure in the microwave spectrum (M. Goto and S. Saito, Astrophys. J

To evaluate individual expansion coefficients composing fitting parameters of the Born-Oppenheimer corrections to Dunham's coefficients Y(ij) that have been given analytically with the Delta(B) and Delta(omega) formalism, we examined the consistency of analytic expressions for those corrections with Watson's assertion of the experimental inseparability of nonadiabatic corrections Q(a, b)(r) for a molecule

The energy levels upsilon(4)=1, upsilon(4)=2, and upsilon(4)=3 of DCCI have been analyzed by using the fundamental nu(4)(1) (470-520 cm(-1)) and the overtone 2nu(4)(0) (955-1005 cm(-1)) bands together with the hot bands 2nu(4)(0,2)<--nu(4)(1), 3nu(4)(1,3)<--2nu(4)(0,2), and 3nu(4)(1)<--nu(4)(1). In the case of HCCI the previously studied hot bands connected to nu(4) have been completed by adding 3nu(4)(1)<--nu(4)(1)

We have calculated the electronic states of Rb(2) by multireference configuration interactions using the averaged relativistic effective small-core potential and the core-polarization potential. The potential energy curves for a large number of states dissociating into from 5s+5s up to 7s+5s asymptotic limits are calculated and the spectroscopic constants are reported. The spin-orbit effects for the