THE ABSORPTION SPECTRUM OF $N_{2}H_{2}$ AND $N_{2}D_{2}$ MOLECULES.

The absorption spectrum of the products of a high frequency discharge through hydrazine was investigated in the visible, ultraviolet and vaccum ultraviolet regions. In addition to the well known bands of ammonia, two new absorptions were observed: at $3450 {\\AA}$ a weak continuous band, and between 1580 and $1720 {\\AA}$R a progression of eight discrete bands. Earlier mass spectrometric studies of Foner and $Hudson^{1}$ had shown that the discharge products are $NH_{3}, N_{2}H_{2}, H_{2}$ and $N_{2}$. Therefore the new absorption features are assigned to $N_{2}H_{2}$ (diimide). The vacuum ultraviolet bands in the deuterated species are less diffuse than those of $N_{2}H_{2}$. They have the typical appearance of perpendicular type bands of near prolate symmetric top molecules. The infrared absorption spectrum of the same discharge products was previously investigated by Blau and $Hochheimer^{2}$ in the region $400-3250 cm^{-1}/$ We have re-investigated the region $3000-3250 cm^{-1}$ under higher resolution; the strongest features can be interpreted as line like Q heads of the parallel and perpendicular components of an hybrid band of a near prolate symmetric top; the rotational constants are in reasonable agreement with those expected for $N_{2}H_{2}$.