|Molecule Types Vibrational Structure Vibrational Energy Levels and Franck-Condon Factors||<Prev Next>|
One of these items will be present for each vibrational mode
under each electronic state.
The number is controlled by the nModes at the molecule level.
|Symmetry||Symmetry of this vibrational mode. Note that this setting is shared with every state in the molecule.|
|vMin||Minimum vibrational quantum number for this mode to include in the basis. Note that an implementation restriction in the current version means that values of vMin > 0 are likely to slow calculations for intensities considerably.|
|vMax||Maximum vibrational quantum number for this mode to include in the basis. Note that in more recent versions of the program the default for this is 3 if there are 3 or less vibrational modes, otherwise 0. This avoids asking for very large calculations by accident; if the product over all modes of (vMax+1) is more than 50 or so the calculation is likely to become rather slow.|
|xOmega||Anharmonic terms. The diagonal
vibrational energy is taken as:
Omega(v+d/2) + xOmega(v+d/2)2 + yOmega(v+d/2)3 + zOmega(v+d/2)4 + gll2where d is the degeneracy of the mode. Note the sign of xOmega - this is often taken as negative in the Dunham expansion for diatomic molecules. For polyatomic molecules, xOmega is typically written as xii, yOmega as xiii and zOmega as xiiii. For terms involving more than one mode, such as x12, add a Vibrational Perturbation.
|epsOmega||Renner-Teller term. The operator multiplying this is q+2|Λ|e−2i|Λ|φ
with the e∓2i|Λ|φ
term imposing a ΔΛ = −Δl =
±|Λ| selection rule. For Π states the term
used in the literature is often ½εω(q+2e−2iφ+q−2e+2iφ),
so the value required here may be half that quoted in the
|lx0||Elements of the matrix M-½ l for the first nucleus for this vibrational mode in units of 1/sqrt(amu). Repeated for each nucleus, or absent if the l matrix is not being used.|
Right click on the item in the constants
window for the following operations in addition to the
|Sort||Sort modes into standard order, i.e. Symmetry and then descending order of frequency. Note that this option re-orders the modes in every state of the molecule.|
|Global Shift Up||Shift this mode up in every
state in the molecule. Note that the "Move Up" item on
the same menu only moves the values up for the selected
||Shift this mode down in every state in the molecule. Note that the "Move Up" item on the same menu only moves the values up for the selected state|