Enzymatic Etching of Single Crystals of Naphthalene

Abstract

IT was previously observed¹ that when crystals of naphthalene, which had been grown from the vapour phase, were immersed in an aqueous suspension of soil pseudomonads for about 10 min at room temperatures, a small number (about 10² cm⁻²) of well-defined, pyramidal pits were produced on the principal habit faces {00l}. This result was tentatively interpreted to mean that preferential attack of the naphthalene by the pseudomonads occurred at the regions of emergence of dislocations, a view which was consonant with: (i) the conclusions of Kochendorfer², who indicated that dislocations lying in, {010} planes, having a Burgers vector in the [001] direction, might be possible in naphthalene; (ii) the results of Koslovskii³, who observed growth spirals on the {00l} faces of certain naphthalene crystals; (iii) the more recent work of Sears⁴, who also proffered evidence for dislocations emergent at {00l} faces. The result agreed with the molecular interpretation of Davies and Evans⁵ concerning the oxidative metabolism of naphthalene by microbial enzymes.