The scales of Raga Neelamani are as follows :
Aarohanam (Ascending) : S R2 M1 P D1 N3 S’
Avarohanam (Descending) : S’ N3 D1 P M1 R2 S
It is a Janya raga, derived from Sarasangi which is 27th on the Melakarta Scale.
The mood of this raga is pathos and at times despair. It is a very minor raga with very few songs. In addition to enna kavi padinalum, one verse of chinnanjiru kiliye by Subramanya Bharati is often sung in this raga. It is better associated with the famous song Nalamdana from the film Thillana Mohanambal.
The raga sounds very similar to Shivaranjani, even though the scales are dissimilar. This is because the ragas are very close if we make a modal shift of the tonic note (graha bhedam) in Shivaranjani using panchama (P) as shadjam (S). I have tried to illustrate this for you below. You will see that the shift brings Shivaranjani close to Neelamani except for the nishadam N3.
Note : The 12 notes in the octave are named as below. Please note that C is used as Sa for the sake of simplicity as the scale is relative in Carnatic Music. Also note that the scales paint only a superficial picture of the raga as the gamakas(ornamentations) are a very important part of a raga.