Heterodyne measurements of hot bands and isotopic transitions of N2O near 7.8 µm

Heterodyne frequency measurements are reported for absorption transitions of N₂O in the frequency range from 1257 to 1335 cm^?1. The measurements use a CO laser as a transfer oscillator whose frequency is measured directly against combinations of frequencies of two stabilized CO₂ lasers whose frequencies are well known. A tunable diode laser is locked to the N₂O absorption feature and the frequency difference is measured between the diode laser and the CO laser. Thev ₃ fundamental bands of the¹⁵N¹⁴N¹⁶O and¹⁴N¹⁵N¹⁶O isotopes are reported. Measurements are also given for the 00⁰2–00⁰1, 02⁰1–02⁰0, and 02²1–02²0 vibrational transitions of N₂O. A table of frequencies is given for the 00⁰2–00⁰0 band near 2560 cm^?1 based on these and earlier measurements.