Creating a sequential list of letters with R

Question

I want to be able to create a sequence of letters in R ,to assist in importing data from a SPSS file

It's convinient to create a sequence of numbers, for example

seq(1,1000)
[1] 1 2 3 4 5 6 ... 1000

paste("something_",1:12,sep="")
[1] something1 something2 ... something12

But is there any functionality wihch can be used for appending, pasting, or creating sequences of letters like this?

paste("This_",a:z,sep="")
[1]This_a This_b This_c ... This_4z