We recommend the following:

4 mL vials manufactured from polypropylene or glass with PTFE/silicone septa.

8 mL screw-thread sample vials manufactured from either clear 33 expansion borosilicate clear glass (Type 1, Class A) or 51A amber glass. 

We recommend using the Omega 5SC-TT-K-30-36.

Yes, most reactions need to have some sort of stirring however some chemistries (such as ones that utilize enzymes) rely upon shaking as stir bars could mechanically destroy the catalysts.

If the reaction is homogeneous (only one phase) then typically 300-500 rpm stirring suffices.

If however, the reaction is biphasic (solid-liquid or liquid-liquid) then stirring becomes critical because reactivity is dependent upon the interface interactions. For instance, Prof. David MacMillan’s group at Princeton University has several chemistries that use inorganic bases in organic solvents - here very high stir rates are required (ie >700 rpm).

Maximum stirring is not always beneficial especially if you have small reaction volumes because your reaction could get dispersed across the vial and no longer have contact with the stir bar.

We use cross-shaped stir bars as they tend to be more stable at higher RPMs.

If not centered, stirring turns into tumble stirring (end-over-end) which might be sufficient for some cases but likely not for all.

If your reaction is homogeneous this likely won't matter much.

The total radiant flux of the different wavelength LEDs we measured on a sample of one of each is:

450nm – 3.4 W @ 100% intensity
420nm – 1.8 W @ 100% intensity
365nm – 1.5 W @ 100% intensity

In a recent study, we measured the light density as 19.63 mW/mm2 at the vial location.