Here you can download MSMS:
http://mgltools.scripps.edu/downloads#msms
To render:
# smaller render, no normalization, high aasamling
[tachyonpath] -res 1920 1080 -aasamples 36 -add_skylight 1.0 %s -format PSD48 -o %s.psd
# huge render, high aasamling
[tachyonpath] -res 12460 9620 -aasamples 36 -add_skylight 1.0 %s -normalize -format PSD48 -o %s.psd
# below command can be used to set resolution when you don't want to force a resolution in tachyon
display resize 1280 1024