Abstract
Gas electron diffraction (GED) is a powerful tool of structural chemistry. This field is currently undergoing important change because of the recent development of multichannel real-time data acquisition procedures which are more versatile than the conventional photographic detection methods. Direct detection enables studies of transient species and time-resolved investigations using pulsed electron beams. It is a characteristic of GED that closely spaced bond distances and angles are not resolved by the data due to molecular disorder in gases. Therefore, ab initio geometries are useful in GED studies, because calculated differences between bond distances and angles can be used to constrain least squares GED data analyses. This area of structural chemistry, involving interactive quantum mechanical and experimental studies, is currently also undergoing an important development, because the accuracy of the calculated constraints can be tested in a novel way by MP2- gradient optimizations.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
Similar content being viewed by others
References
Hargittai, I. and Hargittai, M. (eds.) (1988) ‘Stereochemical Applications of gas phase electron diffraction’ vols. A and B, VCH.
Schäfer, L. (1976) ‘Electron diffraction as a tool of structural chemistry’, Appl. Spectrosc. 30, 123–149.
Ewbank, J. D., Schäfer, L., Paul, D. W., Benston, O. J., and Lennox, J. C. (1984) ‘Real- time data acquisition for gas electron diffraction’, Rev. Sei. Instrum. 55, 1598–1603.
Ewbank, J. D., Schäfer, L., Paul, D. W., Monts, D. L., and Faust, W. L. (1986) ‘Improvements in real-time data acquisition for gas electron diffraction’, Rev. Sei. Instrum. 57, 967–972.
Ewbank, J. D., Paul, D. W., Schäfer, L., and Bakhtiar, R. (1989) ‘Real-time electron diffraction. Part III: Image transfer via fiber optics’, Appl. Spectrosc, 43, 415–419.
Schäfer, L. and Ewbank, J. D. (1988) ‘Experiments aimed at extending the applicability of gas electron diffraction using real-time procedures’, Acta Chem. Scand., A42, 358- 366.
Ewbank, J. D., Faust, W. L., Luo, J. Y., English, J. T., Monts, D. L., Paul, D. W., Dou, Q., and Schäfer, L. (1992) ‘Instrumentation for gas electron diffraction employing a pulsed electron beam synchronous with photoexcitation’, Rev. Sei. Instrum. 63, 3352- 3358.
Chiu, N. S., Ewbank, J. D., Askari, M., and Schäfer, L. (1979) ‘Molecular orbital constrained gas electron diffraction studies’, J. Mol. Struct., 54,185–195.
Chiu, N. S., Sellers, H. L., Schäfer, L., and Kohata, K. (1979) ‘Molecular orbital constrained electron diffraction studies. Conformational behavior of 1,2 dimethylhydrazine’, J. Am. Chem. Soc, 101, 5883–5889. 255
Hemelrijk, D. Van, Enden, L. Van den, Geise, H. J., Sellers, H. L., and Schäfer, L. (1980) ‘Structure determination of 1-butene by gas electron diffraction, microwave spectroscopy, molecular mechanics and molecular orbital constrained electron diffraction’, J. Am. Chem. Soc, 102,2189–2195.
Klimkowski, V. J., Ewbank, J. D., Alsenoy, C. Van, Scarsdale, J. N., and Schäfer, L. (1982) ‘Molecular orbital constrained electron diffraction studies. 4. Conformational analysis of the methyl ester of glycine’, J. Am. Chem. Soc, 104,1476–1480.
Schäfer, L., Ewbank, J. D., Siam, K., Chiu, N. S., and Sellers, H. L., (1988) ‘Molecular orbital constrained electron diffraction studies: The concerted use of electron diffraction and quantum chemical calculations’, in Hargittai I. and Hargittai M. (eds.) ‘Stereochemical Applications of gas phase electron diffraction’, VCH, vol. A, 301–320.
Schäfer, L., Siam, K., Ewbank, J. D., Caminati, W., and Fantoni, A. C. (1987) ‘Ab initio studies of structural features not easily amenable to experiment: Some surprising applications of ab initio geometries in microwave spectroscopic conformational analyses’, in Maksic, Z. B. (ed.), ‘Modelling of structure and properties of molecules’, Horwood Ltd., 79–90.
Pulay, P. (1969) ‘Ab initio calculation of force constants and equilibrium geometries in polyatomic molecules’, Mol. Physics, 17, 197–204.
Pulay, P. (1979) ‘An efficient ab initio gradient program’, Theoret. Chim. Acta, 50, 299- 312.
Schäfer, L., Alsenoy, C. Van, and Scarsdale, J. N. (1982) ‘Estimates for systematic empirical corrections of consistent 4–21G ab initio geometries’, J. Mol. Struct. 86, 349- 364.
Schäfer, L. (1983) ‘The ab initio gradient revolution in structural chemistry: the importance of local molecular geometries and the efficacy of joint quantum mechanical and experimental procedures’, J. Mol. Struct. 100, 51–73.
Hehre, W. J., Radom, L. Schleyer, P. von R., and Pople, J. A. (1986) ‘Ab initio molecular orbital theory’, Wiley, New York.
Ramek, M., Cheng, V. K. W., Frey, R. F., Newton, S. Q., and Schäfer, L. (1991) ‘The case of glycine continued: some contradictory SCF results’, J. Mol. Struct., 235,1–10.
Frey, R. F., Coffin, J., Newton, S. Q., Ramek, M., Cheng, V. FL W., Momany, F. A., and Schäfer, L. (1992) ‘Importance of correlation-gradient geometry optimization for molecular conformational analyses’, J. Am. Chem. Soc. 114, 5369–5377.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 1993 Springer Science+Business Media Dordrecht
About this chapter
Cite this chapter
Schäfer, L., Ewbank, J.D. (1993). Recent Advances in Gas Electron Diffraction and Structural Studies by Join Quantum Mechanical and Experimental Procedures. In: Fausto, R. (eds) Recent Experimental and Computational Advances in Molecular Spectroscopy. NATO ASI Series, vol 406. Springer, Dordrecht. https://doi.org/10.1007/978-94-011-1974-0_16
Download citation
DOI: https://doi.org/10.1007/978-94-011-1974-0_16
Publisher Name: Springer, Dordrecht
Print ISBN: 978-94-010-4871-2
Online ISBN: 978-94-011-1974-0
eBook Packages: Springer Book Archive