ABSTRACT:In an effort to exploit chemistry for information science, we have constructed a system to send a message powered by a combustion reaction. Our system uses the thermal excitation of alkali metals to transmit an encoded signal over long distances. A message is transmitted by burning a methanol-soaked cotton string embedded with combinations of high, low, or zero levels of potassium, rubidium, and/or cesium ions. By measuring the intensities at the characteristic emission wavelengths of each metal in the near-infrared, 19 unique signals can be distinguished. We have built a custom telescope to detect these signals from 1 km away for nearly 10 min. The signal is isotropic, is self-powered, and has a low background. A potential application of this platform is for search and rescue signaling where another layer of information can be transmitted, in addition to the location of the beacon. This work, which seeks to encode and transmit information using chemistry instead of electronics, is part of the new field of "infochemistry".I n this paper, we describe a chemically powered light source that acts as a simple signaling beacon over long distances. The beacon is fueled by the combustion of methanol. Our atomic emission beacon is prepared by doping a cotton wick with metal salts; these salts are atomized during combustion and release thermally excited atomic emission. We detect the emission from metal atoms using a custom telescope equipped with bandpass filters and photodiodes (Figure 1). This work builds on our previous work using an "infofuse" to transmit messages encoded in flashes of atomic emission. 1−3 These efforts, along with previous work done using microfluidics 4 and bacteria-based encoded messages 5 aim to explore the nascent field of infochemistry.Infochemistry seeks to use chemical reactions to encode bits of information that can be used for communication or computation. This approach is a different way of thinking about information technology, which is now dominated by binary signals. By removing the assumption that communication must be electronic, one is free to imagine new chemicalbased platforms for information transmission. 6 These new systems can draw from all chemical and physical phenomena and need not rely solely on solid-state physics. We envision that these new platforms, such as the atomic emission beacon, will provide simple solutions for transmitting information in resource-limited environments, such as the scene of a disaster.The previously developed infofuse is capable of sending data at rates of several bits per second but suffers from one major drawback, the message is short-lived, usually only lasting a few seconds. 1,3 This brevity could make detection difficult if the detector is not aimed at the right place at exactly the right time. The atomic emission beacon seeks to remedy this issue and can transmit its message steadily for several minutes at the expense of lower information density. The atomic emission beacon Figure 1. Atomic emission beacon composed of a cotton wick d...