Exponential transformation of molecular orbitals. II. General formulation for UHF calculations and application to diatomics and molecular fragments

1981 ◽  
Vol 20 (6) ◽  
pp. 1285-1300 ◽  
Author(s):  
A. Bruceñta ◽  
P. Vermeulin ◽  
P. Archirel ◽  
G. Berthier
Keyword(s):  
Molecular Orbitals ◽  
Molecular Fragments ◽  
Exponential Transformation

Exponential transformation of molecular orbitals

1994 ◽  
Vol 101 (5) ◽  
pp. 3862-3865 ◽  
Author(s):  
Jürg Hutter ◽  
Michele Parrinello ◽  
Stefan Vogel
Keyword(s):  
Molecular Orbitals ◽  
Exponential Transformation

Quasi-Barrierless Submolecular Motion in Mechanically Interlocked Carbon Nanotubes

2020 ◽  
Author(s):  
Julia Villalva ◽  
Belén Nieto-Ortega ◽  
Manuel Melle-Franco ◽  
Emilio Pérez
Keyword(s):  
Density Functional ◽  
Close Contact ◽  
Tight Binding ◽  
Energetic Cost ◽  
Molecular Fragments ◽  
Activation Barriers ◽  
Flat Surfaces ◽  
Different Types ◽  
Atomically Flat ◽  
Derivatives Of

The motion of molecular fragments in close contact with atomically flat surfaces is still not fully understood. Does a more favourable interaction imply a larger barrier towards motion even if there are no obvious minima? Here, we use mechanically interlocked rotaxane-type derivatives of SWNTs (MINTs) featuring four different types of macrocycles with significantly different affinities for the SWNT thread as models to study this problem. Using molecular dynamics, we find that there is no direct correlation between the interaction energy of the macrocycle with the SWNT and its ability to move along or around it. Density functional tight-binding calculations reveal small (<2.5 Kcal·mol-1) activation barriers, the height of which correlates with the commensurability of the aromatic moieties in the macrocycle with the SWNT. Our results show that macrocycles in MINTs rotate and translate freely around and along SWNTs at room temperature, with an energetic cost lower than the rotation around the C−C bond in ethane.<br>

Structural and chemical characteristics of model molecular fragments petroleum resins

2018 ◽  
Vol 59 (3) ◽  
Author(s):  
S.A. Shutkova ◽  
◽  
M.Yu. Dolomatov ◽  
M.M. Dolomatova ◽  
A.M. Petrov ◽  
...  
Keyword(s):  
Chemical Characteristics ◽  
Molecular Fragments
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