Measurements of rovibrational constants of CaH+ for studying possible time variation of electron-proton mass ratio

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K13545
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Atomic/Molecular/Quantum electronics
• Research Institution: Sophia University
• Principal Investigator: Okada Kunihiro 上智大学, 理工学部, 教授 (90311993)
• Co-Investigator(Kenkyū-buntansha): 梶田 雅稔 国立研究開発法人情報通信研究機構, 電磁波研究所時空標準研究室, 主任研究員 (50359030)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: イオントラップ / クーロン結晶 / 分子イオン / 陽子-電子質量比 / CaH+ / レーザー冷却 / 光解離

Outline of Final Research Achievements

The purpose of the present work is determination of rovibrational constants of CaH+, which is one of the best candidates for studying possible time variation of the proton-electron mass ratio by ultraprecise vibrational spectroscopy. In order to measure the rovibrational constants, we have constructed a cryogenic linear Paul trap for rotational cooling of Coulomb crystallized CaH+ ions and laser spectroscopy system consisting of a mid-infrared laser and a violet semiconductor laser. We also performed a photodissociation experiment in order to determine the rovibrational constants. We successfully observed the photodissociation reaction CaH+ + hν → Ca+ + H. The lower limit of the photodissociation cross section was determined by the measurement of the photodissociation rate. This experimental progress paved the way to measure the rovibrational constant of CaH+ through LIF measurements.

Free Research Field

原子分子・量子エレクトロニクス