Equilibrium structure and fundamental vibrational wavenumbers in monomeric methyllithium CH3Li: an ab initio study

摘要: Abstract Highly correlated ab initio calculations employing large basis sets are reported for monomeric methyllithium, CH 3 Li. Combining theoretical vibrational corrections and experimental ground-state rotational constants from a recent microwave investigation of three isotopomers the equilibrium geometry Li was determined: r e ( CLi )=196.22(34) pm , )=109.58(14) ∠ (HCH)=105.69(24)°. The error bars chosen such that purely estimate structure is also covered. Correlated harmonic [CCSD(T)/cc-pVQZ+aug(C)] anharmonic [MP2/MT(ae)] force fields provide values fundamental wavenumbers in which differ significantly those observed an argon matrix, except degenerate bending modes. Possible explanations this discrepancy discussed. It concluded reliable gas phase needed order to resolve discrepancy. Many spectroscopic predicted.