San Diego-based Accelerys and Santa Clara-based Symyx announced this morning that the two are in a all-stock merger to create a new, scientific information software firm. The firms said that Symyx shareholders will receive 0.7802 shares of Accelerys common stock for each share of Symyx, creating a firm with a market capitalization of $335M and around $150M in cash. The combined firm will be headquartered in San Diego.