Molecular mechanics. The MM3 force field for hydrocarbons. 2. Vibrational frequencies and thermodynamics

1989 ◽  
Vol 111 (23) ◽  
pp. 8566-8575 ◽  
Author(s):  
Jenn Huei Lii ◽  
Norman L. Allinger
1999 ◽  
Vol 18 (22) ◽  
pp. 4574-4583 ◽  
Author(s):  
Helena Hagelin ◽  
Mats Svensson ◽  
Björn Åkermark ◽  
Per-Ola Norrby

2019 ◽  
Vol 123 (13) ◽  
pp. 2991-2999 ◽  
Author(s):  
R. J. Shannon ◽  
B. Hornung ◽  
D. P. Tew ◽  
D. R. Glowacki

1992 ◽  
Vol 57 (4) ◽  
pp. 675-680 ◽  
Author(s):  
Erik de Vos Burchart ◽  
Bert van der Linden ◽  
Herman van Bekkum ◽  
Bastiaan van de Graaf

The effect of the adsorption of p-xylene on the all-silica MFI-structure is simulated with our molecular mechanics model. From experimental measurements it is known that the symmetry of the framework changes from monoclinic (space group P21/n.1.1.) towards orthorhombic (space group P212121) upon adsorption of p-xylene up to eight molecules per unit cell. The experimentally observed change in the geometry of the zeolite upon p-xylene adsorption is compared with that calculated by molecular mechanics. For the calculations our force field for all-silica zeolites is used in combination with the MM3 force field for organic molecules. Parameters for the organic-zeolite interactions are obtained by combination of the two force fields.


1990 ◽  
Vol 11 (7) ◽  
pp. 848-867 ◽  
Author(s):  
Norman L. Allinger ◽  
Fanbing Li ◽  
Liqun Yan

1989 ◽  
Vol 111 (23) ◽  
pp. 8551-8566 ◽  
Author(s):  
Norman L. Allinger ◽  
Young H. Yuh ◽  
Jenn Huei Lii

1992 ◽  
Vol 57 (4) ◽  
pp. 681-686 ◽  
Author(s):  
Erik de Vos Burchart ◽  
Herman van Bekkum ◽  
Bastiaan van de Graaf

The molecular mechanics force field developed for all-silica structures is extended with parameters for tetrahedral aluminium. With this force field and the MM3 force field for organic molecules the effects of isomorphous substitution in the MFI framework are examined (4 Al/unit cell) with tetrapropyl ammonium (TPA) as the charge compensating cation. The results indicate a slight preference for the positions 2, 9, 5, 12, and 6 and the by mirror symmetry related positions. The differences in energy are mainly due to the differences in the zeolite framework energy.


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