DIPOLE MOMENT EXPANSION OF WATER

$^{a}$C. Camy-Peyret and J. -M. Flaud, Mol, Phys. \emph{32}, 523 (1976). $^{b}$J. -M. Flaud and C. Camy-Peyret, J. Mol. Spectrosc. 51, 142 (1974). $^{3}$J. -M. Flaud, C. Camy-Peyret, J. -Y. Mandin and G. Guelachvili, Mol. Phys. \emph{34}, 413 (1977); C. Camy-Peyret, J. -M. Flaud and R. A. Toth, J. Mol. Spectrosc. \emph{67}, 117 (1977).""Author Institution: Laboratoire de Physique, Mol\'eculaire et d'Optique AtmospheriqueWe show how we have been able to determine from experimental measurements of vibration-rotation line intensities, some coefficients appearing in the expansion of the dipole moment with respect to normal coordinates. In particular, the combined study of ``cold” and ``hot” bands allows to resolve the ambiguity of signs always present in such problems. From the study of the $\nu_{2}, 2\nu_{2}, \nu_{1}, \nu_{3}, \nu_{1}+\nu_{2}, \nu_{2}+\nu_{3},\nu_{1}-\nu_{2}, \nu_{3}-\nu_{2}$ and $2\nu_{2}-\nu_{2}$ bands, we have obtained: \begin{eqnarray*} \begin{array}{rlllll} ^{2}\mu_{x}&=& 0.1794_{6}& \pm &0.0020D&(a)\\ ^{1}\mu_{x}&=&-0.0217_{0}& \pm &0.0010 D&(b)\\ ^{3}\mu_{z}&=& 0.0971_{4} &\pm& 0.0018 D&(b)\\ ^{22}\mu_{x}&=& 0.013 &\pm& 0.002 D&(b)\\ ^{12}\mu_{x}&=&(-0.843& \pm& 0.18)\times 10^{-1} &D\; (c)\\ ^{23}\mu_{z}&=& (0.267& \pm& 0.010)\times10^{-1}& D\; (c) \end{array} \end{eqnarray*