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. |
Omega | Vibrational Frequency |
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}
+ g_{ll}^{2}
where 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 x_{ii},
yOmega as x_{iii} and zOmega as x_{iiii}. For
terms involving more than one mode, such as x_{12}, add a Vibrational
Perturbation. |
yOmega | |
zOmega | |
gll | |
epsOmega | Renner-Teller term. The operator multiplying this is q_{+}^{2|Λ|}e^{−2i}^{|Λ|φ}
+ 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_{+}^{2}e^{−2i}^{φ}+q_{−}^{2}e^{+2i}^{φ}),
so the value required here may be half that quoted in the
literature. |
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. |
ly0 | |
lz0 | |
... |
Right click on the item in the constants
window for the following operations in addition to the
standard ones: