The last two decades have seen tremendous growth in the development of techniquesfor molecular state control. The goal of achieving complete control over the quantum states of a molecule is motivated by a plethora of applications ranging from many-body physics to precise tests of fundamental physics. The level of control required for such applications involves state-preparation of molecules not just in their ground rotational states but also in any quantum state of choice. Also important is to be able to sustain them for a duration long enough to probe them, and to re-prepare the molecules quickly. This thesis presents a glimpse into the applications of molecular ion quantum control and for this purpose, our molecule of choice is SiO+ (Silicon monoixde cation). I start off with the description of a technique to pump SiO+ to a narrow distribution of rotational states (DeltaN=2) around a target state of choice. Following that, I discuss the spectroscopy of SiO+ at and beyond equilibrium bond lengths as the first application of molecular quantum control. To measure the constants of molecular Hamiltonian at energies far from equilibrium bond-lengths, the molecules were pumped to and sustained at high rotational energies. State detection was carried out via the C2Pi state, which was discovered and characterized simultaneously. Another interesting application of molecular quantum control is to study and control chemical reactions at the quantum level. With the ability to sustain molecular control over a long period of time, we were able to study the reaction of SiO+ with H2 as a function of the rotational states of SiO+. We discovered that rotation of the SiO+ molecules increases the rate of its reaction with H2. These results were supported by calculations from Prof. Hua Guo and Prof. Anyang Li. In the remainder of the thesis, I talk about the progress towards non-destructive state detection of SiO+. For this purpose, we performed double resonance spectroscopy and determined the line positions of R(0) and P(1) transitions on (X; v = 0) to (B; v = 0) with an accuracy of approximately 50MHz. Attempts to detect fluorescence were, however, not successful. Nevertheless, the determination of line positions sets the path for using fluorescence as state detection and Doppler cooling of SiO+ in the future. I conclude the thesis with a quick discussion of another prospective application of molecular quantum control in the form of blackbody thermometry and the potential of SiO+ for such a measurement.

Creator

• Venkataramanababu, Sruthi

DOI

• https://doi.org/10.21985/n2-ectb-pd56

Subject

• Optics
• Molecular physics
• Quantum physics

Language

• en

Alternate Identifier

• http://dissertations.umi.com/northwestern:15950
• etdadmin_upload_880868

Keyword

• diatomic molecular control
• rotational state control
• state dependent chemistry
• molecular spectroscopy
• molecular ions

Date created

• 2022-01-01

Resource type

• Dissertation

Rights statement

• In Copyright