Work

Precise Determination of Excited State Rotational Constants and Black-Body Thermometry in Coulomb Crystals of Ca+ and CaH+

Year: 2025

Type: article

Abstract: We present high-resolution rovibronic spectroscopy of calcium monohydride molecular ions (CaH + ) cotrapped in a Coulomb crystal with calcium ions ( 40 Ca + ), focusing on rotational transitions in the | X 1 Σ +, ν ″ = 0⟩ → | A 1 Σ +, ν ′ = 2⟩ manifold. By resolving individual P and R branch transitions with record precision and using Fortrat analysis, we extract key spectroscopic constants for the excited state | A 1 Σ +, ν ′ = 2⟩, specifically, the band origin, the rotational constant, and the centrifugal correction. Additionally, we demonstrate the application of high-resolution rotational spectroscopy of CaH + presented here as an in situ probe of the local environmental temperature. We correlate the relative amplitudes of the observed transitions to the underlying thermalized ground-state rotational population distribution and extract the blackbody radiation (BBR) temperature.

Source: The Journal of Physical Chemistry A

DOI: 10.1021/acs.jpca.5c00229

Authors: Swapnil Patel, Kenneth R. Brown

Institution: Duke University

Language: English

Topic: Molecular Spectroscopy and Structure

Subfield: Spectroscopy

Field: Chemistry

Domain: Physical Sciences

Open Access status: green

Funder: Army Research Office

Awards: G1432373144, G5815720985, G7452299184