A global double many-body expansion potential energy surface is reported for the electronic ground state of H2S by fitting accurate ab initio energies calculated at the multireference configuration interaction level with the aug-cc-pVQZ basis set, after slightly correcting semiempirically the dynamical correlation by the double many-body expansion-scaled external correlation method. The functio...

We present the basic formal and numerical aspects of higher-degree interpolated moving least squares (IMLS) methods. For simplicity, applications of these methods are restricted to two 1-D test cases: a Morse oscillator and a 1-D slice of the potential energy surface. For these two test cases, we systematically examine the effect of parameters in the weight function (intrinsic to IMLS methods),...

We examine the quantisation of a collective Hamiltonian for the two-baryon system derived by us in a previous paper. We show that by increasing the sophistication of the approximations we can obtain a bound state or a resonance not too far removed from the threshold with the quantum numbers of the deuteron. The energy of this state is shown to depend very sensitively on the parameters of the mo...

The availability of collisional rate coefficients is a prerequisite for an accurate interpretation of astrophysical observations, since the observed media often harbour densities where molecules are populated under non-local thermodynamic equilibrium conditions. In the current study, we present calculations of rate coefficients suitable to describe the various spin isomers ofmultiply deuterated...

The high resolution absorption spectrum of monodeuterated water, HDO, has been recorded by Intracavity Laser Absorption Spectroscopy (ICLAS) in the 12145–13160 cm 1 region. The achieved sensitivity (noise equivalent absorption on the order of amin 10 9 cm ) allowed detecting transitions with line strengths as weak as 10 27 cm/molecule which is about 50 times lower than the weakest line intensit...

The low-temperature rotational (de-) excitation of C3 (X 1 g ) by collisions with He ( S ) is studied using an ab initio potential energy surface (PES). This PES has been calculated using the singleand double-excitation coupledcluster approach with noniterative perturbational treatment of triple excitations [CCSD(T)] and the augmented correlation-consistent triplebasis set (aug-cc-pVTZ) with bo...

The crossed beams reaction of the phenyl radical (C6H5) with 1,2-butadiene (CH3HCCCH2) was studied under single collision at two collision energies. The crossed beams data were combined with electronic structure calculations on the C10H11 potential energy surface. The reaction was found to follow indirect scattering dynamics via an addition of the phenyl radical with its radical center to the s...

The unimolecular dissociation of the (v1,0,0) pure OH stretching states of hypochlorous acid ~HOCl! in the ground electronic state is investigated for v156 – 9. The dynamics calculations are performed on an accurate potential energy surface and employ filter diagonalization in connection with an imaginary absorbing potential. The dependence of the linewidth ~or dissociation rate! on the total a...

The weak absorption spectrum of dideuterated water, D2O, has been recorded by Intracavity Laser Absorption Spectroscopy (ICLAS) between 11400 and 11900 cm . This spectrum is dominated by the 3m1 + m2 + m3 and the m1 + m2 + 3m3 centered at 11500.25 and 11816.64 cm , respectively. A total of 530 energy levels belonging to eight vibrational states were determined. The rovibrational assignment proc...