Molecular Design of a Room-Temperature Maser

A computational molecular design strategy, complemented by UV/vis absorption and time-resolved electron paramagnetic resonance (EPR) spectra measurements, is employed to guide the search for active molecules for a room temperature maser that can achieve continuous-wave operation. Focusing on linear polyacenes and diaza-substituted forms, our goal is to model how important maser properties are influenced by acene length and location of nitrogen substitution. We find that tetracene, its diaza-substituted forms (5,11-, 1,7-, and 2,8-diazatetracene), and anthracene possess singlet to triplet intersystem crossing rates highly favorable toward masing. The diaza-substituted forms of pentacene (6,13-, 5,12-, 1,8-, and 2,9-diazapentacene) also stand out as ideal candidates due to their similarity to the working pentacene prototype. A steady-state population analysis suggests the working conditions under which continuous-wave masing can be achieved for these molecules. Operational frequencies are estimated from calculated zero field splitting parameters.

一种计算分子设计策略，辅以紫外/可见吸收和时间分辨电子顺磁共振（EPR）光谱测量，被用于指导寻找可实现连续波运行的室温微波激射器的活性分子。着眼于线性多并苯及其二氮杂取代形式，我们的目标是模拟并苯长度和氮取代位置如何影响微波激射器的重要性能。我们发现并四苯、其二氮杂取代形式（5,11 -、1,7 -和2,8 -二氮杂并四苯）以及蒽具有非常有利于产生微波激射的单重态到三重态的系间窜越速率。并五苯的二氮杂取代形式（6,13 -、5,12 -、1,8 -和2,9 -二氮杂并五苯）由于与正在使用的并五苯原型相似，也作为理想的候选物脱颖而出。稳态布居分析表明了这些分子能够实现连续波微波激射的工作条件。根据计算的零场分裂参数估算了工作频率。