ZLA CTLR LOSES SEPARATION AT APPROX FL200 DURING CROSSOVER BTWN ARR AND DEP ACFT WHEN SEVERAL XMISSIONS WERE CONFUSED.

Narrative

ACFT #1 WAS A VNY DEP EBOUND OVER PMD CLBING TO FL190. ACFT #2 WAS A BUR ARR AT FL200 CLRED TO CROSS 10 MI E OF PMD AT 14000 FT. ACFT #1 WAS WAITING TO CLR AN ONT ARR OVER PMD THAT WAS DSNDING TO FL200. WHEN ACFT #1 WAS CLR OF THE XING TFC WAS READY TO CLB I NOTICED ACFT #2 HADN'T STARTED HIS DSCNT YET. I CLRED ACFT #2 TO AMEND HIS ALT AND MAINTAIN FL200 AND CALLED THE TFC. THE READBACK WAS UNCLR AND ONLY A PARTIAL CALL SIGN OF ACFT #2. IN THE MIDDLE OF REISSUING THE CLRNC; I NOTICED ACFT #2 HAD LEFT FL200 AND WAS DIVING TO MAKE HIS XING RESTR. I ISSUED ACFT #2 TO EXPEDITE THROUGH FL180 TO MAINTAIN 14000 FT AND ISSUED ACFT #1 TO CLB AND MAINTAIN FL210. ACFT #2 ADVISED HE WAS RESPONDING TO AN RA AND WAS CLBING. I TURNED ACFT #2 40 DEGS L AND TURNED ACFT #1 20 DEGS L. THERE WERE SOME CONTRIBUTING FACTORS TO THE ERROR. ACFT #1 WAS CLBING OUT AT 265 KTS. 8 MI BEHIND HIM WAS AN A320 CLBING AT OVER 300 KTS. I ISSUED A SPD TO THE A320 AND ACFT #1 READ THE CLRNC BACK. THIS FORCED ME TO REISSUE THE CLRNCS. A CRJ2 WAS OVER PMD AT 14000 FT AND HAD NOT DSNDED INTO APCH CTL AIRSPACE. APCH CALLED AND REQUESTED COM WITH THE CRJ2. I HAD ALREADY ISSUED THE FREQ CHANGE TO THE PLT AND I REISSUED THE CLRNC. THE CRJ READ THE CLRNC BACK ONCE MORE. THE CRJ2 DIDN'T START HIS DSCNT FOR ABOUT 45 MORE SECONDS. THIS REQUIRED A POINTOUT TO ANOTHER SECTOR. I ALSO HAD TFC SLOWLY CLBING OUT OF 12000 FT FOR 15000 FT HEAD-ON WITH THE CRJ2. AN ACFT CHKED ON MY FREQ LEVEL AT FL370 THAT I DIDN'T HAVE TRACK CTL OF. I LOCATED THE ACFT AND ISSUED HIM THE CORRECT FREQ. THESE ALL ADDED TO WORKLOAD AND COMPLEXITY AT THE SECTOR.