ANALYSIS OF THE ETHYL CHLORIDE NU(9) BAND BY MEANS OF THE ASSIGNMENT OF NEW FAR-INFRARED LASER LINES

Ten new FIR laser lines have been recently observed in C2H5Cl. We assi gn them to absorptions in the A-type v(9) band of C2H5 Cl-35. From the ir assignment we could identify some more absorption lines in the high resolution optoacoustic spectrum of this molecule, obtained using CO2 lasers with a tunability of 1 GHz around each line. The theoretical a nalysis of the spectrum has been extended from J(max) = 23 to J(max) = 64. Further improvements need a better knowledge of the centrifugal c oefficients in the fundamental vibrational level. We also give new val ues of the molecular constants of C2H5 Cl-35 in the excited vibrationa l level. (C) 1998 Published by Elsevier Science B.V.