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The Application of the Method of Pseudopotentials to Hydrides of Silicon and their Methyl Analogs
Author(s) -
Janoschek Rudolf,
Sax Alexander,
Halevi E. Amitai
Publication year - 1983
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.198300008
Subject(s) - chemistry , excited state , ground state , basis set , organosilicon , silylene , silicon , valence (chemistry) , atomic orbital , ionization energy , atomic physics , computational chemistry , ionization , ion , density functional theory , quantum mechanics , organic chemistry , physics , electron
The method of local pseudopotentials is applied to the calculation of several ground‐ and excited‐state properties of selected silicon compounds. The calculated ground‐state geometries and ionization potentials of the silicon hydrides: SiH, SiH 2 , SiH 3 and SiH 4 and of the ions SiH + , SiH − , SiH + 3 and SiH − 3 are in good agreement with the best theoretical and experimental results — whenever these are available. All the singly excited states of SiH 2 originating from a given occupied orbital are evaluated in a single calculation. For those few valence states for which reliable experimental and theoretical data exist, agreement is good. The conceptual and computational advantages of transforming the basis set of silicon into a set of atomic pseudoorbitals are demonstrated by repeating the latter computations with increasingly large sets of atomic orbitals, ranging from [3 s , 3 p ] to [3 s , 3 p , 3 d , 4 s , 4 p ]. The utility of this procedure for reliable and economical calculations on organosilicon compounds is illustrated with a similar set of computations on the ground‐state properties and vertical excitation energies of Si(CH 3 ) 2 . The effect of methyl substitution on the ground‐state properties of silylene and on the energetic ordering of its excited states is discussed.