the bps 
 were wet - chemically synthesized using a seed - mediated - growth method 
 in aqueous solution . subsequently , the 
 bps in solution were drop cast on a clean transparent glass substrate . the glass substrate was placed on a three - axis piezo - controlled scanning 
 stage on top of an inverted microscope , carrying a three axes - controlled 
 afm head ( nanowizard 3 , jpk instruments , berlin ) on top . this setup 
 allows for simultaneous afm manipulation , dark - field scattering spectroscopy , 
 and pl spectroscopy . for the latter , a 405 nm cw excitation
bulk gold shows photoluminescence 
 ( pl ) with a negligible quantum yield of 1010 , which can be increased by orders of magnitude in the case of gold 
 nanoparticles . 
 this bears huge potential to use noble metal nanoparticles 
 as fluorescent and unbleachable stains in bioimaging or for optical 
 data storage . 
 commonly , the enhancement of the pl yield is attributed 
 to nanoparticle plasmons , specifically to the enhancements of scattering 
 or absorption cross sections . tuning the shape or geometry of gold 
 nanostructures ( e.g. , via reducing the distance between two nanoparticles ) 
 allows for redshifting both the scattering and the pl spectra . however , 
 while the scattering cross section increases with a plasmonic redshift , 
 the pl yield decreases , indicating that the common simple picture 
 of a plasmonically boosted gold luminescence needs more detailed consideration . 
 in particular , precise experiments as well as numerical simulations 
 are required . 
 hence , we systematically varied the distance between 
 the tips of two gold bipyramids on the nanometer scale using afm manipulation 
 and recorded the pl and the scattering spectra for each separation . 
 we find that the pl intensity decreases as the interparticle coupling 
 increases . 
 this anticorrelation is explained by a theoretical model 
 where both the gold - intrinsic d - band hole recombination probabilities 
 as well as the field strength inside the nanostructure are considered . 
 the scattering cross section or the field strength in the hot - spot 
 between the tips of the bipyramids are not relevant for the pl intensity . 
 besides , we not only observe pl supported by dipolar plasmon resonances , 
 but also measure and simulate pl supported by higher order plasmonic 
 modes .