Can you excite argon atoms with a high intensity beam of ultrasonic wave ?
Short answer: ultrasonic audio can not transmit nearly the amount of energy needed to excite argon gas to the point that the electrons will change valence, causing the gas to emit light (which I’m guessing is what you’re after). Long answer: sound is a wave through a medium. Ultrasonic energy is vibrations in the air in the room. When that vibrating air hits a glass tube, the tube vibrates (but a lot of the energy probably goes into heat). The vibrating tube vibrates the argon gas inside it (and again, much of the energy goes into heat). If you could magically create an ultrasonic wave strong enough, you would melt the glass with heat long before you would transmit enough energy to the argon gas to cause electrons to change valence levels, which is what would make the gas glow.
