Microwave spectrum, structure and dipole moment of methyl nitrate

Cox, A. Peter; Waring, Stephen

doi:10.1039/tf9716703441

Cited by 76 publications

(27 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Some correction must also be made for the case of the out-of-plane hydrogen substi tution. However, as noticed in the case of methyl nitrate [11] the effect of the torsion here is smaller than for in-plane substitution. Even after correction, the calculated out-of-plane co-ordinates in cis propanal ~ 0.88 Ä are somewhat small compared with typical values, 0.89-0.90 Ä [12].…”

Section: Molecular Structure (I) Cis Propanalmentioning

confidence: 77%

Cis and Gauche Propanal: Microwave Spectra and Molecular Structures

Randell

Cox

Hillig

et al. 1988

Zeitschrift Für Naturforschung A

Self Cite

View full text Add to dashboard Cite

The microwave spectra of twelve isotopic species of cis propanal (CH3CH2CHO) and six isotopic forms of the less stable gauche rotamer have been studied to determine accurate structural parame ters for both conformers. The following bond lengths (Ä) and angles (°) were derived: (9) 125.1 (9) 128.2 (3) Introduction Propanal (CH3CH2CHO) exists in the form of two rotational conformers in the gas phase, cis and gauche. Recently we reported [1] an extension to previous microwave work on propanal [2, 3, 4] which enabled us to compare the barriers to internal rotation of the methyl group in the two conformers. The purpose of the present paper is to present accurate structures for both conformers.The microwave spectrum of cis propanal is straight forward and has been extensively studied [2,4,5]. With the present work, isotopic data are now avail able for substitution at each atomic position in the molecule.The microwave spectrum of gauche propanal is more complicated because doublets, appear even in the ground state, due to + tunnelling. Study of the spectrum has also been limited because of the un Reprint requests to Dr. A. Peter Cox, School of Chemistry, Department of Physical Chemistry, University of Bristol, Bristol, England, BS8 ITS. favourable energy difference between the conformers, AH (gauche -cis) = 420(27) cm "1 [5], Recently we have obtained the A rotational constant for several species by the use of radiofrequency microwave dou ble resonance techniques. This information and data from assignment of carbon-13 spectra have been used to derive accurate structural information for the gauche conformer. ExperimentalThe microwave frequencies measured in the present work are given in Tables 1 and 2. The CH2DCH2CHO species were prepared and studied as described in Reference [6]. The cis car bon-13 species were studied in natural abundance using a pulsed molecular beam Fourier transform microwave spectrometer at Ann Arbor, details of which may be found in [7]. The high energy gauche form was not detected by this technique.The remaining cis and gauche species studied in this work were observed using the Bristol 100 kHz Stark 0932-0784 / 88 / 0300-283 $ 01.30/0. -Please order a reprint rather than making your own copy.

show abstract

Section: Molecular Structure (I) Cis Propanalmentioning

confidence: 77%

Cis and Gauche Propanal: Microwave Spectra and Molecular Structures

Randell

Cox

Hillig

et al. 1988

Zeitschrift Für Naturforschung A

Self Cite

View full text Add to dashboard Cite

show abstract

“…These terms, which are known to play a critical role in the simulation of condensed phases, were "Reference [18]. Reference [19].…”

Section: The Van Der Waals (Vdw) Parametersmentioning

confidence: 99%

“…A comparison of the calculated structure of methyl nitrate at the various levels of theory with the experimental structure determined by Cox and Waring [18] …”

Section: Force Field Developmentmentioning

confidence: 99%

Molecular Modeling of Energetic Materials: The Parameterization and Validation of Nitrate Esters in the COMPASS Force Field

2000

View full text Add to dashboard Cite

To investigate the mechanical and other condensed phase properties of energetic materials using atomistic simulation techniques, the COMPASS force field has been expanded to include high-energy nitro functional groups. This report presents the parameterization and validation of COMPASS for nitrate esters (-ON0 2 ). The functional forms of this force field are of the consistent force field type. The parameters were derived with an emphasis on the nonbonded parameters, which include a Lennard-Jones 9-6 function for the van der Waals (vdW) term and a Coulombic term for an electrostatic interaction. To validate the force field, molecular mechanics calculations and molecular dynamics simulations have been made on a variety of molecules containing the nitrate ester functionality. Using this force field, excellent agreement has been obtained between the calculated and experimental values for molecular structures, vibrational frequencies, liquid densities, heats of vaporization, crystal structure, mechanical properties and lattice energy.n Acknowledgments

show abstract

“…The influence of nitrate groups, linked to C atoms, on the configuration of polynitrates has been studied for the stable fl modification of 1,2,3-propanetriol trinitrate (PTTN) by X-ray analysis. It is also of great interest to compare the structural data with the results of a microwave-spectroscopy study of methyl nitrate (MN) in the gas phase (Cox & Waring, 1971;Dixon & Wilson, 1961 of the molecule is presented in Fig. 1.…”

mentioning

confidence: 99%