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We analyze the validity of a commonly used identification between structuresof the virtual photon $\gamma^*\to Q\bar Q$ and vector meson $V\to Q\bar Q$transitions. In the existing studies of $S$-wave vector-meson photoproductionin the literature, such an identification is typically performed in thelight-front (LF) frame while the radial component of the meson wave function israther postulated than computed from the first principles. The massivephoton-like $V\to Q\bar Q$ vertex, besides the $S$-wave component, alsocontains an extra $D$-wave admixture in the $Q\bar Q$ rest frame. However, therelative weight of these contributions cannot be justified by any reasonablenonrelativistic $Q\bar Q$ potential model. In this work, we investigate therelative role of the $D$-wave contribution starting from the photon-likequarkonium $V\to Q\bar Q$ transition in both frames: in the $Q\bar Q$ restframe (with subsequent Melosh spin transform to the LF frame) and in the LFframe (without Melosh transform). We show that the photon-like transitionimposed in the $Q\bar Q$ rest frame leads to significant discrepancies with theexperimental data. In the second case we find that the corresponding total$J/\psi(1S)$ photoproduction cross sections are very close to those obtainedwith the "$S$-wave only" $V\to Q\bar Q$ transition, both leading to a gooddescription of the data. However, we find that the "$S$-wave only" transitionleads to a better description of photoproduction data for excited heavyquarkonium states, which represent a more effective tool for study of $D$-waveeffects. Consequently, the predictions for production of excited states basedon the photon-like structure of $V\to Q\bar Q$ transition should be treatedwith a great care due to a much stronger sensitivity of the $D$-wavecontribution to the nodal structure of quarkonium wave functions.

$D$-wave effects in diffractive electroproduction of heavy quarkonia from the photon-like $V\rightarrow Q\bar Q$ transition