Molecular Symmetry and the Symmetry Groups

2014 ◽  
pp. 18-127
Keyword(s):  
Symmetry Groups ◽  
Molecular Symmetry

Extended molecular symmetry groups

1996 ◽  
Vol 20 (2) ◽  
pp. 331-349 ◽  
Author(s):  
Pavel Sold�n
Keyword(s):  
Symmetry Groups ◽  
Molecular Symmetry

Identification of Molecular Symmetry Groups

1963 ◽  
Vol 31 (8) ◽  
pp. 569-570
Author(s):  
James B. Calvert
Keyword(s):  
Symmetry Groups ◽  
Molecular Symmetry

Transition states from molecular symmetry groups: Analysis of non-rigid acetylene trimer

1991 ◽  
Vol 72 (1) ◽  
pp. 33-73 ◽  
Author(s):  
Richard G.A. Bone ◽  
Timothy W. Rowlands ◽  
Nicholas C. Handy ◽  
Anthony J. Stone
Keyword(s):  
Transition States ◽  
Symmetry Groups ◽  
Molecular Symmetry

scholarly journals Artificial Symmetries for Calculating Vibrational Energies of Linear Molecules

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 548
Author(s):  
Thomas M. Mellor ◽  
Sergei N. Yurchenko ◽  
Per Jensen
Keyword(s):  
Symmetry Group ◽  
Group Algebra ◽  
Basis Functions ◽  
Basis Set ◽  
Irreducible Representations ◽  
Molecular Axis ◽  
Symmetry Groups ◽  
Molecular Symmetry ◽  
Linear Molecules ◽  
Group D

Linear molecules usually represent a special case in rotational-vibrational calculations due to a singularity of the kinetic energy operator that arises from the rotation about the a (the principal axis of least moment of inertia, becoming the molecular axis at the linear equilibrium geometry) being undefined. Assuming the standard ro-vibrational basis functions, in the 3N−6 approach, of the form ∣ν1,ν2,ν3ℓ3;J,k,m⟩, tackling the unique difficulties of linear molecules involves constraining the vibrational and rotational functions with k=ℓ3, which are the projections, in units of ℏ, of the corresponding angular momenta onto the molecular axis. These basis functions are assigned to irreducible representations (irreps) of the C2v(M) molecular symmetry group. This, in turn, necessitates purpose-built codes that specifically deal with linear molecules. In the present work, we describe an alternative scheme and introduce an (artificial) group that ensures that the condition ℓ3=k is automatically applied solely through symmetry group algebra. The advantage of such an approach is that the application of symmetry group algebra in ro-vibrational calculations is ubiquitous, and so this method can be used to enable ro-vibrational calculations of linear molecules in polyatomic codes with fairly minimal modifications. To this end, we construct a—formally infinite—artificial molecular symmetry group D∞h(AEM), which consists of one-dimensional (non-degenerate) irreducible representations and use it to classify vibrational and rotational basis functions according to ℓ and k. This extension to non-rigorous, artificial symmetry groups is based on cyclic groups of prime-order. Opposite to the usual scenario, where the form of symmetry adapted basis sets is dictated by the symmetry group the molecule belongs to, here the symmetry group D∞h(AEM) is built to satisfy properties for the convenience of the basis set construction and matrix elements calculations. We believe that the idea of purpose-built artificial symmetry groups can be useful in other applications.

Sign in / Sign up

Export Citation Format

Share Document