“…As a part of the systematic programme -Determination of Gas and Dust Production Rates in Comets (GDPC) -going on in this laboratory (Almeida et al, 1989;Almeida, 1991), the emission band fluxes of cometary CN, C2 and C3 carbon bearing molecular species observed in the coma of comets Bennett (1969i = 1970II) (Babu and Saxena, 1972) West (1975n = 1976 (Sivaraman et al, 1979), P/Halley (1982i) (Goraya et al, 1989a;1989b), Hartley-Good (1985£) (Rautela et al, 1989) and Bradfield (1987s) (Rautela and Sanwal, 1988;Ojha and Joshi, 1989) are analysed. These comets are studied in the framework of the Haser model 1957) by using recently derived fluorescence efficiencies (g-factors) at r^ = 1 AU Almeida et al, 1989) and appropriate numerical parameters which are known for the more prominent species CN, C2 and C3 (Cochran, 1985).…”