Showing papers by "Saurabh Srivastava published in 2012"

An accurate ab initio potential energy curve and the vibrational bound states of X2Σu+ state of H2-

Abstract: Potential energy curve for the X 2 Σ u + state of H 2 - has been computed at the full CI/cc-pVXZ (X = D − Q) level. An analytic function is fitted to the resulting potential energy curve and is then used to calculate the vibrational bound states of H 2 - and compared with those for H2.

Radiative lifetimes of spin forbidden a1Δ → X3Σ- and spin allowed A3Π → X3Σ- transitions and complete basis set extrapolated ab initio potential energy curves for the ground and excited states of CH-.

Abstract: The spin forbidden transition a1Δ → X3Σ− in CH− has been studied using the Breit-Pauli Hamiltonian for a large number of geometries. This transition acquires intensity through spin-orbit coupling with singlet and triplet Π states. The transition moment matrix including more than one singlet and triplet Π states was calculated at the multi-reference configuration interaction/aug-cc-pV6Z level of theory. The computed radiative lifetime of 5.63 s is in good agreement with the experimental (5.9 s) and other theoretical (6.14 s) results. Transition moment values of the spin allowed A3Π → X3Σ− transition have also been calculated at the same level of theory. Calculations show that the corresponding radiative lifetime is considerably low, 2.4 × 10−7 s. Complete basis set extrapolated potential energy curves for the ground state of CH and the ground state and six low lying excited states (a1Δ, b1Σ+, two 3Π, and two 1Π) of CH− are reported. These curves are then used to calculate the vibrational bound states for C...