In Yogic terms it is a type of Nada-spanda for that molecule. I.e. it’s very own vibration (spanda) and the sound (nada) affiliated with it. Those who are familiar with Solid State or Physical Chemistry may know that we are able to reach very close to absolute zero but never exactly absolute zero. As we approach absolute zero, we lose translational and rotational molecular motion and to attain absolute zero, we would also need to loose vibrational molecular motion, which is not possible at an existential level!
Nada Yoga considers two types of sounds- external sound which is Ahata and internal sound which is the Anahata! Ahata utilizes sensory organs like our ears to hear it. Anahata on the other hand cannot be heard by such sensory perception, it can only be experienced when we go within like in deep meditation states of Dhyana and Samadhi. Dhyana and Samadhi are the last two yogic limbs in Ashtanga Yoga.
All kinds of devotional music as chanting, kirtan and so on was meant to help one reach their Anahata (also called the unstruck sound) thru the Ahata. I.e. somewhere utilize the external sensory organ, which is what we have at our disposal as humans to reach the true, inner essential core within us which makes us conscious beings!