ORA-03113: end-of-file on communication channel

Error....
C:\Users>sqlplus / as sysdba
SQL*Plus: Release 11.2.0.1.0 Production on Thu Sep 3 17:58:02 2015
Copyright (c) 1982, 2010, Oracle.  All rights reserved.
Connected to an idle instance.
SQL> startup
ORACLE instance started.
Total System Global Area 3373858816 bytes
Fixed Size                  2180424 bytes
Variable Size            1979714232 bytes
Database Buffers         1375731712 bytes
Redo Buffers               16232448 bytes
Database mounted.
ORA-03113: end-of-file on communication channel
Process ID: 6920
Session ID: 191 Serial number: 3
SQL> exit
Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
C:\Users>

Solutions.....
On the RMAN tool, delete all archivelog.
C:\Users> rman target /
RMAN> startup mount;
RMAN> delete force archivelog all;

Start database...
C:\Users>sqlplus / as sysdba
SQL*Plus: Release 11.2.0.1.0 Production on Thu Sep 3 18:00:52 2015
Copyright (c) 1982, 2010, Oracle.  All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
SQL>

Asifkhan