PGOPHER <Prev Next>

Notes on common error messages

No error message, but no simulated spectrum either

No error message, but the simulated spectrum or exported plot does not look as expected

If the plotted spectrum shows with no net width to lines, either because you have not chosen to set one with "Gau" or "Lor", or because they are rather smaller than the effective plot resolution, then the resulting plot can easily be misleading. This is because of issues with closely spaced transitions - do they combine as one strong line or several weak ones? A physically meaningful plot is only guaranteed if the resolution of the plot, equal to (Fmax - Fmin)/nDF, is significantly less (by a factor of 3 or more) than the linewidth used for the simulation.

"Overflow in Boltzmann for xxxxx: E=-nnnnnnn"

This results from a large negative energy causing the Boltzmann expression exp(-E/kT) to overflow. See the discussion of J range and Partition Functions for a discussion of the causes of this problem and possible solutions.

"Odd and even numbers of electrons in xxxx"

Did you remember to set the right spin for all states? This results if, for example you have the changed the ground state to doublet and left the excited state as singlet (the default).

"Mix of integral and half integral quantum numbers"

The error message means that you have asked PGOPHER to calculate an impossible level, such as a J = 1/2 level for a triplet state. This error message is likely to arise on upgrade to version 5.2, if you are using an observation file prepared for version 5.1. You may need to add the following directive to the start of the observations file:
QuantumNumberFormat 2J
See the upgrading section for more on this.

"Singular Matrix"

When least squares fitting, this normally means that you have floated a parameter (or some combination of parameters) that is not determined from the supplied experimental data. For example, you may well see this if you attempt to float both the upper and lower state origin for a transition, as only the difference is determined. To fix this, float fewer (or at least different) parameters.

"Inconsistent Statistical Weights"

This error occurs when two states with the same J and symmetry but with different statistical weights are included in the same Hamiltonian matrix.