of the field components will form a noticeable fraction of the total spectrum

A comment on Cauchy dispersion {#ss-intro-comments}
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As regards the mismatch terms in the Raman model, Geoff New has remarked (email, 20040121) that there’s a key point about the $\gamma_n$’s that is not made properly in most of the McDonald et al publications; since it is usually said rather enigmatically that the $\gamma$’s are “parameterized” by $\gamma_1$. The point is that if one assumes a Cauchy-type law for the refractive index variation, all the gamma’s are linked by a recurrence relation, and so you only need to specify one of them, from which all the others will follow. The point is made properly (to GN’s knowledge) only in ref [@McDonald-NCLL-1998jmo].

Single-field wideband Raman {#s-singlefieldraman}
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[*Note: This single field derivation does mean some of the approximations as to the “slowness” of the field variation seem somewhat stringent. However, since a conversion to a multi-field model is possible, it would seem the field variation constraints are less stringent than they would first appear.* ]{}

Coupled wavefunction equations {#ss-single-coupled-wnf}
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I start by considering the wave function $\psi$ of a single molecule (e.g. H$_2$) and the electric field $E$, 