Molecule-Based Photonically Switched Half and Full Adder

Abstract

A single molecule logic gate using electronically excited states and ionization/fragmentation can take advantage of the differences in cross-sections for one and two photon absorption. Fault tolerant optically pumped half adder and full adder are discussed as applications. A full adder requires two separate additions, and the logic concatenation that is required to implement this is physically achieved by an intramolecular transfer along the side chain of 2-phenylethyl-N,N-dimethylamine (PENNA). Solutions of the kinetic equations for the temporal evolution of the concentration of different states in the presence of time-varying laser fields are used to illustrate the high contrast ratios that are potentially possible for such devices.

Implementation of simple logic gates on gold–ammonia bonding patterns in different charge states

“…[1][2][3] Faster implementations of logic gates based on optical addressing with laser pulses were proposed by Kompa and Levine [4] which led to further implementations of optical molecular logic machines up to a full adder and finite state machines by Levine and collaborators. [5][6][7][8][9][10] In parallel, several groups have shown that it is possible realize complex combinational logic circuits at the molecular scale, up to half and full addition or subtraction using various external perturbations, i.e., chemical, biochemical, photochemical, optical, electrochemical, electrical, to address the system, encode the inputs and perform the logic operations. [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] We propose here another approach for implementing molecular logic gates.…”

Chemische Strategien für den Aufbau molekularer Logikelemente zur Addition und Subtraktion

“…Aminfragmentierung (durch Photoionisierung mit anschließendem Ladungstransfer). [23] Die Inputs sind durch die beiden benötigten UV-Photonen definiert, die z. B. von zwei verschiedenen Lasern geliefert werden.…”

“…[23] Ein Volladdierer kann drei binäre Ziffern summieren: zwei Inputs (I1 und I2) und den CAR-RY IN (C in ) der vorhergehenden Addition. Das erfordert zwei Halbaddierer HA mit dem Summen-Output des ersten Halbaddierers HA1 (Mittelsumme) als Input des zweiten Halbaddierers HA2 (Schema 8).…”

“…[71] Experimente mit Rastertunnelmikroskopie (STM) und Rastertunnelspektroskopie (STS) haben ergeben, dass sich individuelle Metallionenzentren in diesen Arrays adressieren lassen. [72] [6,13,23,74] Auf dieser Grundlage wurden einfache Logikgatter, kombinatorische Logikschaltkreise (Addierer) und eine komplexere Zustandsmaschine mit einem internen Speicher entwickelt. [75] Es muss allerdings bedacht werden, dass diese Experimente bis jetzt zumeist auf die Gasphase begrenzt sind.…”

Bonding patterns of [Ag2‐alanine]0,± hybrid complexes and the implementation of molecular logic gates

“…Molecular realizations of simple binary gates and complex logic circuits relies on chemical [29,30], photochemical [31][32][33][34][35]36], optical [37][38][39][40], electrical [41][42][43][44] and electrochemical [45,46] addressing at the molecular scale. Finite state molecular machines, that is molecular devices that possess a memory unit whose content is processed by the computing unit together with the inputs, have also been designed [37, 43,[47][48][49].…”