The design, performance, and operation of a broadband (3–26.5 GHz) high resolution microwave spectrometer is described. In comparison to previously developed molecular beam Fabry–Perot resonator spectrometers the design presented here implements some significant improvements: coaxially oriented arrangement (COBRA) formed by confocal pair mirrors incorporating an electromechanical valve employing two pairs antennas, multioctave Fourier-transform (FTMW) instrument providing pulsed excitation...

Abstract We report on first experiences with a pulsed molecular beam microwave Fourier transform spectrometer parallel and resonator axes. This setup shows up high resolution sensitivity.

We present hardware and software details of the pulsed molecular beam microwave Fourier transform (MB-MWFT) spectrometer used in Kiel group. emphasize an automatic scanning facility which greatly increases efficiency MB-MWFT spectroscopy for measurement unassigned spectra.

The microwave spectrum of phenol(H2O) has been recorded using a pulsed molecular beam Fourier transform spectrometer. Twenty a-type transitions have observed and assigned. All are doublets with splittings varying from 1.13 to 4.01 MHz. These interpreted result the internal rotation water molecule. ground state this torsional motion is split into two levels different spin statistical weights. Both treated independently as asymmetric rotor states. resulting rotational constants A=4291.486 MHz,...

The dual-rotor problem of a heterocyclic five-membered ring was studied and an insightful labeling scheme for the molecular symmetry group G₃₆is given.

The microwave spectrum of o-methyl anisole (2-methoxytoluene), CH3 OC6 H4 CH3, has been measured by using a pulsed molecular jet Fourier transform spectrometer operating in the frequency range 2-26.5 GHz. Conformational analysis quantum chemical calculations at MP2/6-311++G(d,p) level theory yields only one stable conformer with Cs structure, which was assigned experimental spectrum. A-E splittings due to internal rotation ring methyl group could be resolved and barrier determined 444.05(41)...

The microwave spectrum of m-methylanisole (also known as 3-methylanisole, or 3-methoxytoluene) was measured using a pulsed molecular jet Fourier transform spectrometer operating in the frequency range 2-26.5 GHz. Quantum chemical calculations predicted two conformers with methoxy group trans cis position related to ring methyl group, both which were assigned experimental spectrum. Due internal rotation all rotational transitions introduced large A-E splittings up several GHz, analyzed newly...

The microwave spectrum of 3,4-dimethylanisole, a molecule containing three methyl groups allowing for internal rotation, was recorded using pulsed molecular jet Fourier transform spectrometer operating in the frequency range from 2.0 to 26.5 GHz. Quantum chemical calculations yielded two conformers with an anti and syn configuration methoxy group, both which were assigned experimental spectrum. Torsional splittings due rotations attached aromatic ring resolved analyzed. rotational-torsional...

The molecular-beam Fourier transform microwave spectrum of 2-acetyl-5-methylfuran is recorded in the frequency range 2-26.5 GHz. Quantum chemical calculations calculate two conformers with trans or cis configuration acetyl group, both which are assigned experimental spectrum. All rotational transitions split into quintets due to internal rotations nonequivalent methyl groups. By using program XIAM, spectra can be simulated standard deviations within measurement accuracy, and yield...

A hint of cassis: By a combination microwave spectroscopy and quantum chemistry, the gas-phase structures Cassyrane stereoisomers its dihydro derivatives have been determined, correlated with their olfactory properties. Superposition analyses (see picture; black Cassyrane, silver Oxane, red O, yellow S) reveal importance 5S configuration on cassis odor, 2S,5R isomers being most intense.

Abstract We report on the rotational spectra of most abundant conformer methyl propionate, CH3CH2COOCH3, recorded with a Fourier transform microwave spectrometer under molecular beam conditions. present accurate constants and centrifugal distortion constants. For propionyl CH3 CH2CO– group methoxy –OCH3 group, barriers 820.46(99) cm−1 429.324(23) cm−1, respectively, were found. spectral analysis, two different computer programs used, code BELGI-Cs-2tops based rho axis method (RAM) XIAM...

The microwave spectrum of linalool, an acyclic monoterpene, was recorded for the first time in range from 9 to 16 GHz. only conformer observed under molecular beam conditions assigned. Fitting rotational with two different programs treating internal rotation yielded constants A = 1.64674020(46) GHz, B 0.68219862(16) C 0.61875100(20) and centrifugal distortion constants. standard deviation fit close experimental accuracy. A-E splittings due one methyl group could be resolved barrier...