He coined this latter term and employed the Greek letter lower case sigma to denote its population parameter.
You know you have seen them - those people who walk around wearing paraphernalia emblazoned with odd symbols like phi, sigma , and pi.
These conical intersections are fundamentally different from the ‘H-vinyl’ structures found in simple alkenes because they involve the interaction of four sigma electrons, as opposed to two pi electrons and two sigma electrons.
The sigma bond occupies the internuclear space, and the two pi bonds are at 90° angles to each other surrounding the carbon-carbon internuclear space.
Alpha, rho, tau, sigma , omega, Ash went over the letters he saw in his mind while Lari just stared, apparently in her own little world.
The sigma particles can be positive, negative, or neutral.
Finally, even if epsilon is the correct reading, in the letter space to its right, where Meritt read part of an iota, are traces of what appears to be a sigma .
The triple bond is composed of one sigma bond from overlap of sp hybrid orbitals, and two pi bonds, from overlap of two sets of p orbitals.
Finally, the final green beam of light was shot straight up at the constellation Sigma .