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  • 1
    Electronic Resource
    Electronic Resource
    Far-infrared spectrum, conformational stability, barriers to internal rotation, ab initio calculations, and vibrational assignment of propionyl chloride (1991)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 95 (1991), S. 539-550 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j100155a011
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  • 2
    Electronic Resource
    Electronic Resource
    Conformational stability, barriers to internal rotation, vibrational assignment and ab initio calculations of fluoroacetyl chloride (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 90 (1989), S. 6840-6851 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The far infrared spectrum (375 to 35 cm−1) of gaseous fluoroacetyl chloride, CH2FC(O)C1, has been recorded at a resolution of 0.10 cm−1. The fundamental asymmetric torsions of the more stable trans (halogen atoms are trans) and the high energy cis conformations have been observed at 116.18 and 49.42 cm−1, respectively, each with several upper state transitions falling to lower frequency. From these spectral data, an asymmetric potential function has been calculated and the potential coefficients are: V1=43±6, V2=1039±36, V3=498±3, V4=149±21, and V6=−10±7 cm−1. The trans to cis and cis to trans barriers are 1455±25 cm−1 (4.16±0.07 kcal/mol) and 914±24 cm−1 (2.61±0.07 kcal/mol), respectively, with an enthalpy difference of 541±45 cm−1 (1.55±0.13 kcal/mol). From studies of the Raman spectra at variable temperatures, values of 509±37 cm−1 (1.46±0.10 kcal/mol) and 310±8 cm−1 (0.89±0.02 kcal/mol) have been determined for the enthalpy difference for the gas and liquid, respectively. The conformational stability, barriers to internal rotation, and fundamental vibrational frequencies which have been determined experimentally, are compared to those obtained from ab initio Hartree–Fock calculations employing both the 3-21G* and 6-31G* basis sets, and to the corresponding quantities obtained for some similar molecules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.456257
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  • 3
    Electronic Resource
    Electronic Resource
    Conformational stability, barriers to internal rotation, normal coordinate analysis, and vibrational assignment of chloroacetyl bromide (1990)
    Springer
    Structural chemistry 1 (1990), S. 61-72 
    Details
    ISSN: 1572-9001
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The infrared spectra (3200 to 30 cm−1) of gaseous and solid chloroacetyl bromide, CH2ClC(O)Br, and the Raman spectra (3200 to 10 cm−1) of the gas, liquid (with depolarization data), and solid have been recorded. From the observed asymmetric torsional transitions, the potential function governing internal rotation of the CH2Cl moiety has been determined with the following coefficients:V 1=336±11,V 2=73±10,V 3=757+7,V 4=103±3, andV 6=5±2 cm−1. This potential function is consistent with s-trans to gauche and gauche to gauche barriers of 963±11 and 709±12cm−1, respectively, and enthalpy difference of 373 ± 24 cm−1 with the dihedral angle of the gauche rotamer being 115°. The enthalpy difference has been determined experimentally from the studies of the Raman spectra at different temperatures to be 359±68 cm−1 (1.03±0.19 kcal mol−1) and 507±24 cm−1 (1.45±0.07 kcal mol−1) for the gas and liquid, respectively, with the s-trans conformer being the more stable conformer in the gas and liquid and the only one present in the annealed solid. A complete assignment of the vibrational fundamentals is proposed from spectral data obtained for the gas, liquid, and solid. The assignment is supported by a normal coordinate calculation utilizing a modified valence force field to obtain the frequencies for the normal vibrations and the potential energy distribution. The results are discussed and compared to the corresponding quantities for some similar molecules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00675785
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  • 4
    Electronic Resource
    Electronic Resource
    Far-infrared spectrum, conformational stability, barriers to internal rotation, normal coordinate calculations, and vibrational assignment for chloroacetaldehyde (1990)
    Springer
    Structural chemistry 1 (1990), S. 459-472 
    Details
    ISSN: 1572-9001
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The far infrared spectrum [350 to 25 cm−1] of gaseous chloroacetaldehyde, ClCH2CHO, has been recorded at a resolution of 0.10 cm−1. The first excited-state transition of the asymmetric torsion of the more stable near s-cis [chlorine atom s-cis to the aldehyde hydrogen atom] conformer has been observed at 26.9 cm−1, with seven additional upper state transitions falling to higher frequency. Additionally, the fundamental torsional transition of the s-trans conformer has been observed at 58.9 cm−1 with two excited states also falling to higher frequency. From these data, the asymmetric torsional potential coefficients have been determined to be:V 1=414±11;V 2 = 191±3;V 3=−203±5;V 4=44±1 andV 6=−26±1 cm−1. The s-cis to s-trans barrier is 500±5 cm−1 (1.43±0.01 kcal mol−1) with the s-cis conformer being more stable by 267±19 cm−1 (0.76±0.05 kcal mol−1) than the s-trans form. The Raman [4000 to 100 cm−1] and infrared (4000 to 400 cm−1] spectra of the gas have been recorded. Additionally, the Raman spectrum of the liquid has been recorded and qualitative depolarization values obtained. Complete vibrational assignments are proposed for both conformers based on band contours, depolarization values, and group frequencies. The assignments are supported by ab initio Hartree-Fock gradient calculations employing the 3–21G* basis set to obtain the frequencies and the potential energy distributions for the normal vibrations for both rotamers. Additional ab initio calculations at the MP4/6-31G* level have been carried out to determine the structural parameters for both conformers. The results are discussed and compared with the corresponding quantities obtained for some similar molecules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00671233
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  • 5
    Electronic Resource
    Electronic Resource
    Procedure, selection and application of plasticity models for a soil (1981)
    New York, NY [u.a.] : Wiley-Blackwell
    International Journal for Numerical and Analytical Methods in Geomechanics 5 (1981), S. 295-311 
    Details
    ISSN: 0363-9061
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences
    Notes: A five-step procedure involving mathematical formulation, identification and determination of parameters and verification is presented for development and selection of appropriate and reliable constitutive law(s) for geologic media. Comprehensive analyses are performed toward determination of an appropriate law for a (artificial) soil. The most suitable model is obtained by critical evaluation of four different plasticity models; here verification and comparisons of predictions with observations from laboratory tests, and with those from two boundary value problems are used as the basis of the selection. The model thus selected is found to be appropriate for applications to relevant practical problems.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nag.1610050306
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  • 6
    Electronic Resource
    Electronic Resource
    Spectra and structure of organophosphorus compounds. XLVIIIFor Part XLVII, see J. R. Durig, C. M. Whang and R. J. Harlan, Vibr. Spectrosc. 1, 19 (1990). - Raman and infrared spectra, conformational stability, vibrational assignments and ab initio calculations of dimethyl(methylthio)phosphine (1992)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 23 (1992), S. 107-124 
    Details
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The Raman spectra (3200-10 cm-1) and infrared spectra (3200-50 cm-1) of dimethyl(methylthio)phosphine, CH3SP(CH3)2, and dimethyl(methyl-d3-thio)phosphine, CD3SP(CH3)2, in the gas and solid forms were recorded. Additionally, the Raman spectra of the liquids were recorded and qualitative depolarization ratios measured. All 36 of the normal modes were assigned and the asymmetric torsion was observed in the far-infrared spectrum of gaseous CH3SP(CH3)2 at 75 cm-1. From a comparison of the vibrational spectra obtained for the fluid phases with those obtained for the amorphous and annealed solids, it is concluded that the molecule exists as a mixture of the cis and trans conformers in the fluid phases with the trans conformer being the more stable form in the liquid and the only one present in the spectra of the annealed solid. However, for the vapor state the cis conformer is the more stable form. The enthalpy difference between the cis and the trans conformers was determined from a variable-temperature study of the Raman spectrum of the liquid to be 199 ± 8 cm-1 (569 ± 23 cal mol-1). A complete vibrational assignment is proposed which is supported by a normal coordinate calculation obtained from the force fields calculated with the ab initio RHF/3-21G* basis set. Full geometry optimizations were carried out with the 3-21G* and 6-31G* basis sets for the transition state to determine the barriers to internal rotation about the CH3S—P bond. All of these results are compared with corresponding data for several other organophosphorus compounds.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jrs.1250230208
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  • 7
    Electronic Resource
    Electronic Resource
    Raman and infrared spectra, conformational stability, barriers to internal rotation, vibrational assignment and ab initio calculation of bromoacetone (1992)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 23 (1992), S. 253-266 
    Details
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Raman (3200 - 10 cm-1) and infrared (3500 - 20 cm-1) spectra were recorded for gaseous and solid bromoacetone (1-bromopropan-2-one), CH2BrC(O)CH3. Additionally, the Raman spectrum of the liquid was recorded and qualitative depolarization values were obtained. These data were interpreted on the basis that the molecule exists predominantly in a gauche conformation of C1 symmetry (dih ∢ BrCCO = 111.8°) in the vapor. In the liquid a second conformer having a trans structure (bromine atom oriented trans to the methyl group) with Cs point group symmetry is also present, and the trans form is the only conformer present in the annealed solid. From a study of the Raman spectrum of the liquid with variable temperatures the trans conformer was determined to be more stable than the gauche form by 385 ± 61 cm-1 (1.09 ± 0.17 kcal mol-1). A complete vibrational assignment is proposed for both conformers. From ab initio Hartree-Fock gradient calculations with the 4 - 31G*/MIDI-4* basis set, optimized geometries for both the gauche and trans conformers were obtained. Similar calculations were also carried out for fluoroacetone and chloroacetone utilizing the 6 - 31G* basis set with electron correlation with secondorder perturbation. The conformational stabilities, barriers to internal rotation and observed fundamental vibrational frequencies for both the gauche and trans conformers of bromoacetone are compared with those calculated with the STO-3G* basis set. The results are discussed and compared with the corresponding quantities obtained for some similar molecules.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jrs.1250230504
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  • 8
    Electronic Resource
    Electronic Resource
    Raman and infrared spectra, conformational stability, barriers to internal rotation, ab initio calculations and vibrational assignment for bromodifluoroacetyl chloride (1993)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 24 (1993), S. 1-10 
    Details
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The Raman (1800-10 cm-1) and infrared (2000-30 cm-1) spectra of bromodifluoroacetyl chloride, CBrF2CClO, are reported for the gas and polycrystalline solid. Additionally, the Raman spectrum of the liquid along with qualitative depolarization ratios have also been obtained. These data have been interpreted on the basis of an equilibrium between the gauche and the trans conformers (bromine atom trans to the chlorine atom) in the gas and liquid phases. From a study of the Raman spectrum of the liquid at various temperatures, a value of 851 ± 56 cm-1 (2.43 ± 0.07 kcal mol-1) was obtained for ΔH with the gauche conformer the more stable form. A similar study of the gas gave a value of 725 ± 150 cm-1 (2.07 ± 0.43 kcal mol-1), again with the gauche rotamer the more stable conformer. Hence the gauche conformer is the predominate rotamer in the gas and liquid and the only conformer present in the annealed solid. Aided by ab initio and scaled computations of the vibrational spectrum with the STO-3G* basis set and, for the trans conformer at the 4-31G*/MIDI-4* level of the theory, complete assignments of observed bands to fundamental vibrations of the gauche conformer are made, whereas partial assignment is reported for the trans conformer. The fundamental torsional mode for the gauche conformer was observed at 46 cm-1 but excited-state transitions were not observed so the potential function governing the conformational interchange could not be determined. Optimized geometries, dipole moments, unscaled and scaled vibrational frequencies and harmonic force fields are reported for both conformers. With the STO-3G*, basis set, the gauche conformer is calculated to be more stable than the trans conformer by 17 cm-1 (48 cal mole-1). These results are compared with the corresponding quantities for some similar molecules.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jrs.1250240102
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  • 9
    Electronic Resource
    Electronic Resource
    Raman and infrared spectra, conformational stability, barriers to internal rotation, ab initio calculations and vibrational assignment of cyanomethyl methyl etherDedicated to Professor Doctor Pedro Jose Aymonio on the occasion of his 65 birthday. (1993)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 24 (1993), S. 851-865 
    Details
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The Raman spectra (3400-10 cm-1) of gaseous, liquid and solid and the infrared spectra (3500-35 cm-1) of gaseous and solid cyanomethyl methyl ether (methoxyacetonitrile), (CN)CH2OCH3, were recorded. The farinfrared spectrum of the gas was recorded at a resolution of 0.10 cm-1 in the region from 370 to 30 cm-1. The fundamental asymmetric torsions of the gauche and trans conformations were observed at 112.5 and 104.6 cm-1, respectively, with the gauche form having two excited-state transitions falling to lower wavenumber. From these data, along with the enthalpy difference and gauche dihedral angle, the asymmetric torsional potential function was calculated with the following coefficients: V1 = 153 ± 9, V2 = -619 ± 8, V3 = 1000 ± 2 and V4 = -100 ± 2 cm-1. From this potential function, the trans to gauche, gauche to gauche and gauche to trans barriers were determined as 512, 1592 and 951 cm-1, respectively, with an enthalpy difference of 439 ± 19 cm-1 (1255 ± 54 cal mol-1) and the gauche conformer the more stable form in the gas phase. The enthalpy difference was also determined experimentally from variable-temperature studies of the Raman spectrum and a value of 337 ± 44 cm-1 (964 ± 126 cal mol-1) was obtained for the liquid with the gauche form more stable. Additionally, the symmetric methyl torsions of both gauche and trans forms were observed at 170.4 and 217.6 cm-1, respectively. On the basis of a one-dimensional model, the barrier to internal rotation of the methyl moiety was determined as 839 cm-1 (2.40 kcal mol-1) for the guache conformer and 947 cm-1 (2.71 kcal mol-1) for the trans form. A complete vibrational assignment is proposed for a gauche-trans equilibrium in the gas and liquid phases from the Raman (3200-10 cm-1) and infrared (3200-35 cm-1) spectra, but in the solid state only the gauche conformer remains. The structural parameters, conformational stability, barriers to internal rotation and fundamental vibrational frequencies which were determined experimentally were compared with those obtained from ab initio calculations employing the RHF/4-31G*, RHF/6-31G* and MP2/6-31 + + G** basis sets. These results were compared with the corresponding quantities obtained for some similar molecules.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jrs.1250241206
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  • 10
    Electronic Resource
    Electronic Resource
    Raman and infrared spectra, conformational stability, barriers to internal rotation, ab initio calculations and vibrational assignment of dichloroacetyl fluoride (1991)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 22 (1991), S. 141-154 
    Details
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The Raman spectra (3200-10 cm-1) of dichloroacetyl fluoride (CHCL2CFO) of the gas, liquid (with qualitative depolarization ratios) and solid were recorded. The infrared spectra (3200-30 cm-1) of the gas and solid were also obtained. All of these data indicate a trans/gauche equilibrium in the gas and liquid whereas only the gauche conformation remains in the solid. A complete vibrational assignment is proposed for both conformers based on the Raman depolarization data, infrared band contours, group frequencies and normal coordinate calculations. From the studies of the Raman spectra at various temperatures, the enthalpy difference between the stable conformers was determined to be 315 ± 68 cm-1 (0.90 ± 0.19 kcal mol-1) (1 kcal = 4.184 kJ) and 180 ± 4 cm-1 (0.51 ± 0.01 kcal mol-1) for the gas and liquid, respectively, with the trans conformer being more stable in the gas but the gauche conformer more stable in the liquid. These experimental results are compared to those obtained from ab initio Hartree-Fock gradient calculations with the RHF/3-21G* and RHF/6-31G* basis sets, and to the corresponding quantities obtained for some similar molecules.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jrs.1250220304
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