Line intensities in the 647.5-nm ammonia band at low temperatures determined by intracavity laser spectroscopy

Abstract

Absolute intensities of three ro-vibrational lines in the 647.5-nm ammonia absorption band are investigated by intracavity laser spectroscopy as a function of temperature (ranging from 180 to 300 K). The absorption lines are at 645.584, 645.712, and 646.050 nm. Their intensities at 299 K are found to be 2.57, 4.01, and 1.94 cm −1atm −1km −1, respectively. A rotational analysis using the derived intensity data is also presented.