new mem

Question 1

why is bending less than stretching

Answer 1

due to bending easier as nuclei is not moving against electron density. Less energy used = lower wavenumber

Question 2

Advantages of FT-RAMAN

Answer 2

Longer wavelength minimises fluorescence
damage from shorter wavelength reduced
spectral resolution of 1 cm^-1

Question 3

Disadvantages of FT-RAMAN

Answer 3

Require higher laser power due to long wavelength (I prop to 1/(wavelength)^4

Question 4

Advantages of dispersive raman

Answer 4

high sensitivity detector
low power can be used
choice of late frequency

Question 5

disadvantages of dispersive raman

Answer 5

possible fluorescence

require calibration

Question 6

define PC

Answer 6

Main data variations. first PC accounts for most variance, successive less

Question 7

define PCA loadings

Answer 7

map of variables - correlation between variables. explains what variables are causing the separation on the scores plot

Question 8

define residual variance

Answer 8

variance remaining in E. Also known as unexplained variance. the difference between the variable and its regression function

Question 9

define PCA scores

Answer 9

map of samples - projected locations of objects onto the principal componentsD

Question 10

Define residuals

Answer 10

error. X =Xstructure + E

Question 11

Define explained variance

Answer 11

the % variance explained by Xstruct. How much variance the model accounts for in the data set

Question 12

Carbs
C-OH
C-OR

Answer 12

1058
1024
3500

Question 13

NUCLEIC ACID

PO2

Answer 13

1225
1084
Moderate 3400

Question 14

AMIDE 2

Answer 14

C-N stretch, N-H bend

1575-1480

Question 15

AMIDE 1

Answer 15

C=O stretch, N-H stretch + inplane bending

1690-1600

Question 16

SATURATED LIPID

Answer 16

3000-2850

Question 17

UNSATURATED LIPID

Answer 17

3100-3000

Question 18

IR range in wavenmuber

Answer 18

13300-4000 NIR
4000-350 mid
350-50 far

Question 19

PCA model equations

Answer 19

X -> model + error