Ž . Spectrochimica Acta Part B 56 2001 629635 Detection of boron nitride radicals by emission spectroscopy in a laser-induced plasma  C. Dutouquet a,  , S. Acquaviva b , J. Hermann a a GREMI, Orleans Uni  ersity  CNRS, P.O. Box 6759, 45067, Orleans Cedex 2, France ´ ´ b Lecce Uni  ersity, Physics Department, Istituto Nazionale Fisica della Materia, P.O. Box 193, 73100 Lecce, Italy Received 12 October 2000; accepted 20 February 2001 Abstract Several vibrational bands of boron nitride radicals have been observed in a plasma produced by pulsed-laser ablation of a boron nitride target in low-pressure nitrogen or argon atmospheres. Using time- and space-resolved emission spectroscopic measurements with a high dynamic range, the most abundant isotopic species B 11 N have been detected. The emission bands in the spectral range from 340 to 380 nm belong to the  1, 0, 1 sequences of Ž 3 3 . the triplet system transition A  X  . For positive identification, the molecular emission bands have been compared with synthetic spectra obtained by computer simulations. Furthermore, B 10 N emission bands have been reproduced by computer simulation using molecular constants which have been deduced from the B 11 N constants. Nevertheless, the presence of the lower abundant isotopic radical B 10 N was not proved due the noise level which masked the low emission intensity of the B 10 N band heads.  2001 Elsevier Science B.V. All rights reserved. Keywords: Pulsed laser ablation; Boron nitride; Plasma spectroscopy; Molecular spectra simulation 1. Introduction Pulsed-laser ablation in the presence of a chemically active gas can result in the formation of molecular species due to gas-phase reactions  This paper was presented at the 1st International Congress on Laser Induced Plasma Spectroscopy and Applications, Pisa, Italy, October 2000, and is published in the Special Issue of Spectrochimica Acta Part B, dedicated to that conference.  Corresponding author. E-mail address: christophe.dutouquet@univ-orleans.fr Ž . C. Dutouquet . between ablated material and ambient gas species. The understanding of these gas-phase reactions is essential for controlling and optimizing the reac- Ž . tive pulsed laser deposition RPLD which was shown to be a promising technique for compound   thin film synthesis 1  4 . Previous studies have   shown 5,6 , that gas-phase reactions depend in a critical manner on the binding energy of the reaction products. Thus, oxides are easily formed during ablation of most materials as oxidation is an exothermic process. On the contrary, nitrida- tion is generally a strongly endothermic process and nitride species are hardly formed in the gas 0584-854701$ - see front matter  2001 Elsevier Science B.V. All rights reserved. Ž . PII: S 0 5 8 4 - 8 5 4 7 01 00188-4