The vibration-rotation spectrum of ammonia gas. I

The vibration-rotation spectrum of ammonia gas in the visible region of the spectrum was photographed on a 1.5 m concave grating spectrograph. A White type multiple reflection tube with an effective path length of 0.5 Km was used. In this region ten new absorption features were observed and vibrationally analyzed. A reassignment of vibrational quantum numbers of six previously reported bands are made. An identification table of the forty-two vibration-rotation bands now known is given. The set of binary anharmonicity constants for overtone and combination bands was determined from the data of this table.