Full Dimensional Franck-Condon Factors for the Acetylene $\tildeA\ ^1A_u-\tildeX\ ^1Σ_g^+$ Transition. II. Vibrational Overlap Factors for Levels Involving Excitation in $ungerade$ Modes Academic Article uri icon


  • A full-dimensional Franck-Condon calculation has been applied to the A ̃ 1A u—X ̃ Σ g+ 1 transition in acetylene in the harmonic normal mode basis. Details of the calculation are discussed in Part I of this series. To our knowledge, this is the first full-dimensional Franck- Condon calculation on a tetra-atomic molecule undergoing a linear-to-bent geometry change. In the current work, the vibrational intensity factors for levels involving excitation in ungerade vibrational modes are evaluated. Because the Franck-Condon integral accumulates away from the linear geometry, we have been able to treat the out-of-plane component of trans bend (ν 4′′) in the linear X ̃ state in the rotational part of the problem, restoring the χ Euler angle and the a-axis Eckart conditions. A consequence of the Eckart conditions is that the out-of-plane component of ν 4′′ does not participate in the …

publication date

  • January 1, 2014