6533b85bfe1ef96bd12bb2f3

RESEARCH PRODUCT

MS-CASPT2 analysis of the UV thermochromism of octamethyltrisilane

R. CrespoJosef MichlMari-carmen Piqueras

subject

SiliconChemistryBiophysicschemistry.chemical_elementCondensed Matter PhysicsAtomic orbitalAbsorption bandExcited statePhysics::Atomic and Molecular ClustersComplete active spacePhysical and Theoretical ChemistryAtomic physicsPerturbation theoryGround stateMolecular BiologyBasis set

description

We interpret the reversal of the direction of the thermochromic shift of the first absorption band of peralkylated oligosilanes as the silicon chain is extended, based on multistate complete active space second-order perturbation theory (MS-CASPT2) calculations for octamethyltrisilane, Si3Me8. The observed shift is attributed to the effect of b1 distortions from ground state equilibrium geometry on vertical excited state energies and intensities. A generally contracted basis set of atomic natural orbitals (ANOs) at a ground state geometry optimized in the second-order Moller–Plesset perturbation theory (MP2) approximation with Dunning's correlation consistent triple-zeta basis set (cc-pVTZ) for the silicon atoms, the 6-31G* set for the carbon atoms and the 6-31G set for the hydrogen atoms was used. §This paper is dedicated to Professor Michael A. Robb on the occasion of his 60th birthday.

https://doi.org/10.1080/00268970500418448