Jet cooled rotational spectrum of methyl lactate

We report here the measurements of the rotational spectra of the main, O-d and four 13C species of methyl-lactate. They have been obtained by free jet millimeter-wave absorption and molecular beam Fourier transform microwave spectroscopy. Only lines of the most stable conformer, the one with the hydroxyl group acting as a proton donor to the carbonylic group oxygen, have been observed. The V3 barrier to internal rotation of the CH3-O methyl group has been determined to be 4.84(2) kJ mol-1. The experimental conformational and structural information are compared to those given by MP2/6-311++G(d,p) calculations

Configuration and Internal Dynamics of CH2ClF\u2022\u2022\u2022Krypton

The molecular complex chlorofluoromethane-krypton has been investigated by Fourier transform microwave spectroscopy in a supersonic expansion. The rotational spectra have been assigned for the CH235ClF\u2022\u2022\u202284Kr, CH235ClF\u2022\u2022\u202286Kr and CH237ClF\u2022\u2022\u202284Kr species, showing that, in the equilibrium configuration, the krypton atom is located out of the ClCF plane, interacting with both F and Cl atoms. All rotational transitions are split in several 35Cl or 37Cl quadrupole components, each of them further split into two lines, due to the tunneling motion of the Kr atom between two equivalent positions, below and above the ClCF plane. The feasible low energy pathway between these two structurally degenerate conformations is described, in a first approximation, by a circular motion around the C-Cl bond, with a barrier estimated to be about 74 cm-1

Jet cooled rotational spectrum of methyl lactate

We report here the measurements of the rotational spectra of the main, O-d and four 13C species of methyl-lactate. They have been obtained by free jet millimeter-wave absorption and molecular beam Fourier transform microwave spectroscopy. Only lines of the most stable conformer, the one with the hydroxyl group acting as a proton donor to the carbonylic group oxygen, have been observed. The V3 barrier to internal rotation of the CH3-O methyl group has been determined to be 4.84(2) kJ mol-1. The experimental conformational and structural information are compared to those given by MP2/6-311++G(d,p) calculations

The global conformational minimum of indan-2-ol

Here we report measurements of the rotational spectra of normal and O-d indan-2-ol, obtained by free jet millimeter-wave absorption spectroscopy. Only lines of the most stable conformer, the one with the hydroxyl group in the axial position and with the hydroxyl hydrogen pointing towards the p system of the benzene ring, have been observed. This experimental evidence is in agreement with the results of density functional (B3LYP/6-311++G**) calculations. A partial r0 structure has been obtained

Experimental configuration, F-F spin-spin coupling and potential energy surface of difluoromethane-Ar

The rotational spectra of normal and 13C species of difluoromethane-argon have been investigated by molecular beam Fourier transform microwave spectroscopy. The obtained results allowed for the determination of the configuration of the complex, based on experimental data. The tunnelling splitting originated by van der Waals motions has been determined to be 193.740(1) and 162.16(8) MHz for the normal and 13C species, respectively. The two vibrational splittings have been used to evaluate a tunnelling barrier of 94(5) cm-1. The fluorine-fluorine nuclear spin-spin coupling constant has been determined, Daa = 0.19(1) MHz

Free jet absorption rotational spectrum of dimethylether \u2013 HCl

The rotational spectrum of dimethylether-hydrogen chloride (see Fig. below) has been assigned and measured by millimetre wave free jet absorption spectroscopy. The HCl moiety is delocalised between the two lone pairs of the ether oxygen, as shown by the wide splitting, 8186(7) MHz, between the two tunnelling components of the ground state. The corresponding barrier to the transfer of HCl from one lone pair to the other one has been evaluated from the experimental data to be 55 cm-1

The mm-Wave Rotational Spectrum of Dichlorodimethylgermane

The rotational spectra of three isotopomers of dichlorodimethylgermane were measured by free jet absorption millimeterwave spectroscopy. A partial r0 structure was obtained. The barrier to internal rotation of the methyl groups is too high to cause splittings observable within our spectral resolution. Corresponding to the resolving power of the experiment, the lower limit to the V3 barrier is about 5.85 kJ/mol

Van der Waals potential energy surface of CH2ClF\u2022\u2022\u2022Xe

The rotational spectra have been assigned for six isotopologues of the CH2ClF\u2022\u2022\u2022Xe, arising from some combinations of the 35Cl, 37Cl, 129Xe, 131Xe, 132Xe and 134Xe isotopes of Cl and Xe. The xenon atom is located out of the ClCF plane, interacting with both F and Cl atoms. All rotational transitions are split in several component lines, due to the 35Cl or 37Cl (or 131Xe) quadrupole components, and to the tunnelling motion of the Xe atom between two equivalent positions, below and above the ClCF plane. The barrier between these two equivalent conformations is ca. 76 cm-

Conformational Landscapes and Free-Jet Rotational Spectrum of Indan-1-ol

Reported here are measurements of the rotational spectra of normal and O-d indan-1-ol, obtained by free jet millimeter-wave absorption spectroscopy. Only lines of the most stable conformer, the one with the hydroxyl group in the equatorial position and with the hydroxyl hydrogen pointing towards the cyclopentene ring, have been observed. This experimental evidence is in agreement with the results of density functional (B3LYP/6-311++G**) calculations. A partial r0 structure has been obtained