* N. NISHIMIYA* AND T. YUKIYA, Department of System Electronics and Information Technology, Department of Applied Computer Science, Tokyo Plolytechnic University, Iiyama 1583, Atsugi City, 243-0297 Kanagawa, JAPAN.

The doppler limited electronic vib--rotational absorption spectrum of A^{3}
_{1}
X^{1}
^{+} system in I^{35/37}Cl is measured in the 11300 -- 13200 cm^{-1} region using a Ti:Sapphire Ring Laser (Coherent 899-21). The 56 bands belonging to (v' = 0
7)
(v'' = 0
6) in I^{35/37}Cl are assigned. The

Dunham coefficients of the X^{1}
^{+} state are calculated based on a global

reduced least squares fitting procedure. The Y''_{10} and Y''_{01} reported by Hedderich *et al.* are

taken into

the calculation because we

do not have sufficient spectrum belonging to v''= 0
2. In the A^{3}
_{1} state, the T'_{v}, B'_{v}_{e/f}, D'_{v} and H'_{v} are

determined instead of the

Dunham coefficients to avoid the distortion of the potential.

%A multiple precision arithmetic library was used in this procedure

To investigate the accuracy of

Dunham coefficients determined

in the X^{1}
^{+} state, the absorption lines of 4'
0'' and 5'
0'' bands are assigned in the 14438 -- 14491 cm^{-1} region where measurements are performed intermittently. Those lines are well positioned within the limit of the standard deviation.