Ab initio study of the spectroscopy of AgBr: a CASSCF + Averaged Coupled Pair Functional approach to the lowest excited states including spin-orbit couplings

J I Amaro-Estrada, A Ramírez-Solís
Journal of Chemical Physics 2009 September 28, 131 (12): 124308
The nine lowest-lying singlet and triplet (X (1)Sigma(+), 2 (1)Sigma(+), 3 (1)Sigma(+), (3)Sigma(+), 1 (3,1)Pi, 2 (3)Pi, and (3,1)Delta) electronic states of AgBr were studied through state-specific Complete Active Space Self-Consistent Field with 16 active electrons in 12 orbitals followed by extensive Averaged Coupled Pair Functional and CIPT2 calculations with large optimized valence basis sets. The spin-orbit effects were included to obtain the Omega fine-structure states arising from the |Lambda S Sigma> parents. Even before the inclusion of the spin-orbit effects, the 2 (1)Sigma(+) and 3 (1)Sigma(+) states present shallow minima near the equilibrium geometry of the ground state. The 2 (1)Sigma(+) state has another minimum around 8.0 a.u. and is attractive up to 20 a.u. The lowest (3,1)Pi states were found to be totally repulsive while the (3,1)Delta states present deep minima around 4.8 a.u. Most of the calculated spectroscopic constants for the ground and B states are slightly improved with respect to the previous theoretical study using the much smaller CASSCF(16,10) reference wave functions [M. Guichemerre et al., Chem. Phys. 280, 71 (2002)]. The observed B<--X transition is confirmed as arising from the singlet-to-singlet 0(+)(2 (1)Sigma(+))<--0(+)(X (1)Sigma(+)) excitation around 31 900 cm(-1). However, at variance with the previous theoretical prediction, the C(Omega=0(+)) state is dominated around the equilibrium geometry of the ground state by the third (1)Sigma(+) state with a small contribution from the 2 (3)Pi state around 43,500 cm(-1); thus the X-C excitation is now explained as arising also from a singlet-to-singlet spin-allowed transition.

Full Text Links

Find Full Text Links for this Article


You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read

Save your favorite articles in one place with a free QxMD account.


Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"