Theoretical study of the effect of substituent and backbone conformation on the electronic properties of symmetrically substituted poly(di‐n‐alkylsilanes)

6533b838fe1ef96bd12a3eed

RESEARCH PRODUCT

Theoretical study of the effect of substituent and backbone conformation on the electronic properties of symmetrically substituted poly(di‐n‐alkylsilanes)

subject

Optimization Energy Gap Propyl Compounds Band gap Ab initio Substituent Geometry General Physics and Astronomy Electronic structure chemistry.chemical_compound Ab initio quantum chemistry methods Computational chemistry Methyl Compounds Conformational Changes Physical and Theoretical Chemistry Band Structure :FÍSICA::Química física [UNESCO]Electronic band structure Alkyl Compounds ; Silanes ; Organic Polymers ; Conformational Changes ; Ab Initio Calculations ; Geometry ; Optimization ; Band Structure ; Affinity ; Ionization Potential ; Energy Gap ; Methyl Compounds ; Ethyl Compounds ; Propyl Compounds Dimethylsilane Organic Polymers Silanes UNESCO::FÍSICA::Química física Crystallography Alkyl Compounds Ionization Potential Affinity chemistry Ethyl Compounds Ionization energy Ab Initio Calculations

description

We present the results of ab initio 3‐21G∗ geometry optimizations and valence effective Hamiltonian (VEH) band structure calculations aimed at determining the evolution of the geometric and electronic (ionization potential, electron affinities, and band gaps) properties of all‐trans poly(dimethylsilane), poly(diethylsilane), poly(di‐n‐propylsilane), and poly(di‐n‐butylsilane) when increasing the size of the alkyl group. In the latter polymer, we have also studied the 7/3 conformation, in order to analyze the effect of the backbone conformation on the geometric and electronic structure. The VEH ionization potentials of all‐trans poly(di‐n‐alkylsilanes) are almost equal, and as experimental photoemission data show, only slight differences are appreciated. The band gap decreases in going from poly(di‐n‐butylsilane) to poly(di‐n‐propylsilane) and to poly(diethylsilane), and increases when passing to poly(dimethylsilane), which coincides with experimental evidences on poly(di‐n‐alkylsilanes). The change from all‐trans to 7/3 conformation of poly(di‐n‐butylsilane) implies an increase of both, ionization potential and band gap, in perfect agreement with experimental photoemission and absorption data. The applicability of VEH to deal with poly(di‐n‐alkylsilanes) is discussed. crespo@uv.es

year	journal	country	edition	language
1994-05-01

10.1063/1.467011 http://hdl.handle.net/10550/20043