Rotational spectra of N$_2^+$: An advanced undergraduate laboratory in atomic and molecular spectroscopy

TL;DR

This paper presents an affordable undergraduate laboratory experiment demonstrating the rotational spectra of N₂⁺ ions through emission spectra analysis, integrating quantum state analysis in advanced atomic and molecular spectroscopy education.

Contribution

It introduces a simple, cost-effective experimental setup and analytical method for studying rotational spectra of N₂⁺ in an educational context, combining rotational and vibrational analysis.

Findings

Successful demonstration of N₂⁺ rotational spectra

Educational integration of quantum state analysis

Affordable experimental approach

Abstract

We describe an inexpensive instructional experiment that demonstrates the rotational energy levels of diatomic nitrogen, using the emission band spectrum of molecular nitrogen ionized by various processes in a commercial AC capillary discharge tube. The simple setup and analytical procedure is introduced as part of a sequence of educational experiments employed by a course of advanced atomic and molecular spectroscopy, where the study of rotational spectra is combined with the analysis of vibrational characteristics for a multifaceted picture of the quantum states of diatomic molecules.